Hi, I got the following error The RPC server is unavailable. 0x800706ba (WIN32: 1722 RPC_S_SERVER_UNAVAILABLE) when I try enroll a certificate from Domain Controller to CA Server.
I was reading posts like: [https://learn.microsoft.com/en-us/answers/questions/743186/the-rpc-server-is-unavailable-0x800706ba-(win32-17](https://learn.microsoft.com/en-us/answers/questions/743186/the-rpc-server-is-unavailable-0x800706ba-(win32-17)
But nothing working for me now.

-Ping from DC to CA Server its Working and ping from CA Server to DC.
-Firewalls its turn off in both sides.
-RPC service its working and running in the DC.
From DC to CA:

Looking for the event views i found this that its the main reason about the problem

Also, I added the group "Domain Controllers" to the local group "Certificate Service DCOM Access" I saw in this post https://social.technet.microsoft.com/Forums/en-US/c0d13777-3f1b-4805-94a2-ac56f3cecbf3/r2-ad-certificate-services-running-on-dc-cant-issue-to-r2win7-clients?forum=windowsserver2008r2general
If I enroll a cert from an other machine its working correctly. (Windows 10 machine cert enroll to CA Server working correctly)

Best Regards, I hope I can fix this error because I dont know whats happens.
If windows firewall is disabled, it should be a firewall device configured on a your network .
try to use the tools provided in the link in my previous answer to check if the RPC port is opened between impacted DC and your CA
Hi @Thameur-BOURBITA
Thats the output executing the tool that u told me, its the same result if I put the CA server, in this case its the DC.
=============================================
Starting portqry.exe -n 192.168.1.191 -e 135 -p TCP ...
Querying target system called:
192.168.1.191
Attempting to resolve IP address to a name...
IP address resolved to DC-1
querying...
TCP port 135 (epmap service): LISTENING
Using ephemeral source port
Querying Endpoint Mapper Database...
Server's response:
UUID: d95afe70-a6d5-4259-822e-2c84da1ddb0d
ncacn_ip_tcp:192.168.1.191[49664]
UUID: 897e2e5f-93f3-4376-9c9c-fd2277495c27 Frs2 Service
ncacn_ip_tcp:192.168.1.191[49724]
UUID: 50abc2a4-574d-40b3-9d66-ee4fd5fba076
ncacn_ip_tcp:192.168.1.191[49693]
UUID: 367abb81-9844-35f1-ad32-98f038001003
ncacn_ip_tcp:192.168.1.191[49677]
UUID: 650a7e26-eab8-5533-ce43-9c1dfce11511 Vpn APIs
ncacn_np:192.168.1.191[\PIPE\ROUTER]
UUID: 12345678-1234-abcd-ef00-0123456789ab
ncacn_ip_tcp:192.168.1.191[49674]
UUID: 0b6edbfa-4a24-4fc6-8a23-942b1eca65d1
ncacn_ip_tcp:192.168.1.191[49674]
UUID: ae33069b-a2a8-46ee-a235-ddfd339be281
ncacn_ip_tcp:192.168.1.191[49674]
UUID: 4a452661-8290-4b36-8fbe-7f4093a94978
ncacn_ip_tcp:192.168.1.191[49674]
UUID: 76f03f96-cdfd-44fc-a22c-64950a001209
ncacn_ip_tcp:192.168.1.191[49674]
UUID: c9ac6db5-82b7-4e55-ae8a-e464ed7b4277 Impl friendly name
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: c9ac6db5-82b7-4e55-ae8a-e464ed7b4277 Impl friendly name
ncacn_ip_tcp:192.168.1.191[49667]
UUID: e3514235-4b06-11d1-ab04-00c04fc2dcd2 MS NT Directory DRS Interface
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: e3514235-4b06-11d1-ab04-00c04fc2dcd2 MS NT Directory DRS Interface
ncacn_ip_tcp:192.168.1.191[49667]
UUID: e3514235-4b06-11d1-ab04-00c04fc2dcd2 MS NT Directory DRS Interface
ncacn_http:192.168.1.191[49671]
UUID: e3514235-4b06-11d1-ab04-00c04fc2dcd2 MS NT Directory DRS Interface
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: f5cc5a18-4264-101a-8c59-08002b2f8426 MS NT Directory NSP Interface
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: f5cc5a18-4264-101a-8c59-08002b2f8426 MS NT Directory NSP Interface
ncacn_ip_tcp:192.168.1.191[49667]
UUID: f5cc5a18-4264-101a-8c59-08002b2f8426 MS NT Directory NSP Interface
ncacn_http:192.168.1.191[49671]
UUID: f5cc5a18-4264-101a-8c59-08002b2f8426 MS NT Directory NSP Interface
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 12345778-1234-abcd-ef00-0123456789ab
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 12345778-1234-abcd-ef00-0123456789ab
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 12345778-1234-abcd-ef00-0123456789ab
ncacn_http:192.168.1.191[49671]
UUID: 12345778-1234-abcd-ef00-0123456789ab
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 12345778-1234-abcd-ef00-0123456789ac
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 12345778-1234-abcd-ef00-0123456789ac
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 12345778-1234-abcd-ef00-0123456789ac
ncacn_http:192.168.1.191[49671]
UUID: 12345778-1234-abcd-ef00-0123456789ac
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 12345778-1234-abcd-ef00-0123456789ac
ncacn_ip_tcp:192.168.1.191[49672]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_http:192.168.1.191[49671]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_ip_tcp:192.168.1.191[49672]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_http:192.168.1.191[49671]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 0b1c2170-5732-4e0e-8cd3-d9b16f3b84d7 RemoteAccessCheck
ncacn_ip_tcp:192.168.1.191[49672]
UUID: 12345678-1234-abcd-ef00-01234567cffb
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 12345678-1234-abcd-ef00-01234567cffb
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 12345678-1234-abcd-ef00-01234567cffb
ncacn_http:192.168.1.191[49671]
UUID: 12345678-1234-abcd-ef00-01234567cffb
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 12345678-1234-abcd-ef00-01234567cffb
ncacn_ip_tcp:192.168.1.191[49672]
UUID: b25a52bf-e5dd-4f4a-aea6-8ca7272a0e86 KeyIso
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: b25a52bf-e5dd-4f4a-aea6-8ca7272a0e86 KeyIso
ncacn_ip_tcp:192.168.1.191[49667]
UUID: b25a52bf-e5dd-4f4a-aea6-8ca7272a0e86 KeyIso
ncacn_http:192.168.1.191[49671]
UUID: b25a52bf-e5dd-4f4a-aea6-8ca7272a0e86 KeyIso
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: b25a52bf-e5dd-4f4a-aea6-8ca7272a0e86 KeyIso
ncacn_ip_tcp:192.168.1.191[49672]
UUID: 8fb74744-b2ff-4c00-be0d-9ef9a191fe1b Ngc Pop Key Service
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 8fb74744-b2ff-4c00-be0d-9ef9a191fe1b Ngc Pop Key Service
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 8fb74744-b2ff-4c00-be0d-9ef9a191fe1b Ngc Pop Key Service
ncacn_http:192.168.1.191[49671]
UUID: 8fb74744-b2ff-4c00-be0d-9ef9a191fe1b Ngc Pop Key Service
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 8fb74744-b2ff-4c00-be0d-9ef9a191fe1b Ngc Pop Key Service
ncacn_ip_tcp:192.168.1.191[49672]
UUID: 51a227ae-825b-41f2-b4a9-1ac9557a1018 Ngc Pop Key Service
ncacn_np:192.168.1.191[\pipe\lsass]
UUID: 51a227ae-825b-41f2-b4a9-1ac9557a1018 Ngc Pop Key Service
ncacn_ip_tcp:192.168.1.191[49667]
UUID: 51a227ae-825b-41f2-b4a9-1ac9557a1018 Ngc Pop Key Service
ncacn_http:192.168.1.191[49671]
UUID: 51a227ae-825b-41f2-b4a9-1ac9557a1018 Ngc Pop Key Service
ncacn_np:192.168.1.191[\pipe\b67e98146d26edb4]
UUID: 51a227ae-825b-41f2-b4a9-1ac9557a1018 Ngc Pop Key Service
ncacn_ip_tcp:192.168.1.191[49672]
UUID: 6b5bdd1e-528c-422c-af8c-a4079be4fe48 Remote Fw APIs
ncacn_ip_tcp:192.168.1.191[49670]
UUID: 7f1343fe-50a9-4927-a778-0c5859517bac DfsDs service
ncacn_np:192.168.1.191[\PIPE\wkssvc]
UUID: 1ff70682-0a51-30e8-076d-740be8cee98b
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 378e52b0-c0a9-11cf-822d-00aa0051e40f
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 33d84484-3626-47ee-8c6f-e7e98b113be1
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 86d35949-83c9-4044-b424-db363231fd0c
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 86d35949-83c9-4044-b424-db363231fd0c
ncacn_ip_tcp:192.168.1.191[49666]
UUID: 3a9ef155-691d-4449-8d05-09ad57031823
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 3a9ef155-691d-4449-8d05-09ad57031823
ncacn_ip_tcp:192.168.1.191[49666]
UUID: b18fbab6-56f8-4702-84e0-41053293a869 UserMgrCli
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: b18fbab6-56f8-4702-84e0-41053293a869 UserMgrCli
ncacn_ip_tcp:192.168.1.191[49666]
UUID: 0d3c7f20-1c8d-4654-a1b3-51563b298bda UserMgrCli
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 0d3c7f20-1c8d-4654-a1b3-51563b298bda UserMgrCli
ncacn_ip_tcp:192.168.1.191[49666]
UUID: 552d076a-cb29-4e44-8b6a-d15e59e2c0af IP Transition Configuration endpoint
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 552d076a-cb29-4e44-8b6a-d15e59e2c0af IP Transition Configuration endpoint
ncacn_ip_tcp:192.168.1.191[49666]
UUID: 2e6035b2-e8f1-41a7-a044-656b439c4c34 Proxy Manager provider server endpoint
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: 2e6035b2-e8f1-41a7-a044-656b439c4c34 Proxy Manager provider server endpoint
ncacn_ip_tcp:192.168.1.191[49666]
UUID: c36be077-e14b-4fe9-8abc-e856ef4f048b Proxy Manager client server endpoint
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: c36be077-e14b-4fe9-8abc-e856ef4f048b Proxy Manager client server endpoint
ncacn_ip_tcp:192.168.1.191[49666]
UUID: c49a5a70-8a7f-4e70-ba16-1e8f1f193ef1 Adh APIs
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: c49a5a70-8a7f-4e70-ba16-1e8f1f193ef1 Adh APIs
ncacn_ip_tcp:192.168.1.191[49666]
UUID: a398e520-d59a-4bdd-aa7a-3c1e0303a511 IKE/Authip API
ncacn_np:192.168.1.191[\PIPE\atsvc]
UUID: a398e520-d59a-4bdd-aa7a-3c1e0303a511 IKE/Authip API
ncacn_ip_tcp:192.168.1.191[49666]
UUID: f6beaff7-1e19-4fbb-9f8f-b89e2018337c Event log TCPIP
ncacn_np:192.168.1.191[\pipe\eventlog]
UUID: f6beaff7-1e19-4fbb-9f8f-b89e2018337c Event log TCPIP
ncacn_ip_tcp:192.168.1.191[49665]
UUID: 3473dd4d-2e88-4006-9cba-22570909dd10 WinHttp Auto-Proxy Service
ncacn_np:192.168.1.191[\pipe\eventlog]
UUID: 3473dd4d-2e88-4006-9cba-22570909dd10 WinHttp Auto-Proxy Service
ncacn_ip_tcp:192.168.1.191[49665]
UUID: 2d98a740-581d-41b9-aa0d-a88b9d5ce938
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 8bfc3be1-6def-4e2d-af74-7c47cd0ade4a
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 1b37ca91-76b1-4f5e-a3c7-2abfc61f2bb0
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: c605f9fb-f0a3-4e2a-a073-73560f8d9e3e
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 0d3e2735-cea0-4ecc-a9e2-41a2d81aed4e
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 2513bcbe-6cd4-4348-855e-7efb3c336dd3
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 20c40295-8dba-48e6-aebf-3e78ef3bb144
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: b8cadbaf-e84b-46b9-84f2-6f71c03f9e55
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 857fb1be-084f-4fb5-b59c-4b2c4be5f0cf
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 55e6b932-1979-45d6-90c5-7f6270724112
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 76c217bc-c8b4-4201-a745-373ad9032b1a
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 88abcbc3-34ea-76ae-8215-767520655a23
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: d09bdeb5-6171-4a34-bfe2-06fa82652568
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 9b008953-f195-4bf9-bde0-4471971e58ed
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: d09bdeb5-6171-4a34-bfe2-06fa82652568
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 697dcda9-3ba9-4eb2-9247-e11f1901b0d2
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: d09bdeb5-6171-4a34-bfe2-06fa82652568
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: fc48cd89-98d6-4628-9839-86f7a3e4161a
ncacn_np:192.168.1.191[\pipe\LSM_API_service]
UUID: 76f226c3-ec14-4325-8a99-6a46348418af
ncacn_np:192.168.1.191[\PIPE\InitShutdown]
UUID: d95afe70-a6d5-4259-822e-2c84da1ddb0d
ncacn_np:192.168.1.191[\PIPE\InitShutdown]
Total endpoints found: 106
==== End of RPC Endpoint Mapper query response ====
portqry.exe -n 192.168.1.191 -e 135 -p TCP exits with return code 0x00000000.