Share via

Migration to new Email Server

Jay Arielle Sabalburo 0 Reputation points
2026-06-09T05:21:34.27+00:00

Last week, we successfully configured or migrated to the new email server (here in our main office where the email server is) with secured email configurations. Outlook email setup on office, on every employee's pc is POP3 server name using the local IP address of the new email server with port 995 for incoming and port 465 for outgoing. We successfully connect all end users to the new email server.

Now, on plant site, second node, they have separate direct internet access which is globe internet and they have this CCProxy server for managing internet, they can ping the local ip address of the new email server. 

I connected on pc of one of our MIS team there via anydesk. We tried to test configure the Outlook email also to be able to connect to the new email server. But as we test the outlook configuration on the pc of one of our team (MIS department), we use the same configuration method here in Makati, but the result we encountered is that, outlook says: 'We couldn't connect to the incoming (POP) server using the specified encryption method. Please check the incoming (POP) server encryption method and try again.'

The pc has microsoft office 2019 installed.

We've tried to turn off firewall on the computer on windows defender but the same result. We use telnet <ip address of the email server> 995, and it shows blank screen with cursor blinking meaning it is connected or open. 

I don't know what other issues to be checked here. 

Outlook | Windows | Classic Outlook for Windows | For business
0 comments

2 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Dora-T 14,355 Reputation points Microsoft External Staff Moderator
    2026-06-09T06:40:56.97+00:00

    Hi Jay Arielle Sabalburo

    Please note that this is a public peer-to-peer community forum. We are not Microsoft Support, and as forum moderators, our role is limited to providing general guidance and directing users to official resources. We do not have access to Microsoft's internal diagnostic tools or to your organization's mail server environment, which limits our ability to investigate the issue further. 

    Based on your description, since Outlook is working correctly for users in the main office using the same POP3/SMTP settings and the issue only occurs at the plant site, the issue appears less likely to be related to Outlook itself and may instead be related to the network environment or the secure connection to the mail server.

    The fact that you can successfully ping the mail server and establish a Telnet connection to port 995 suggests that basic network connectivity is available. However, the error message may indicate an issue with the SSL/TLS negotiation used for the encrypted POP3 connection rather than a connectivity problem.

    I would recommend checking the following:

    • Verify that the SSL/TLS certificate presented by the mail server is trusted on the affected workstation.
    • Confirm that the encryption settings configured in Outlook (for example, SSL/TLS on port 995) match the requirements of the new mail server.
    • Check whether CCProxy, network security devices, antivirus software, or SSL inspection features at the plant site are intercepting or interfering with the SSL/TLS connection.
    • Compare the Outlook and Office build versions between a working workstation in the main office and the affected workstation at the plant site.

    Additionally, if possible, test the same mailbox from the affected network using another email client. This can help determine whether the issue is specific to Outlook or affects all clients attempting to establish a secure POP3 connection.

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

    Was this answer helpful?

  2. AI answer

    2026-06-09T05:22:03.9633333+00:00

    Troubleshooting needs to focus on Outlook’s POP3/SSL configuration and verifying that the remote site is really reaching the correct POP3/SSL service, not just the port.

    Work through these steps in order:

    1. Verify POP3/SSL settings in Outlook
      1. Open Control Panel → Mail → Email Accounts.
      2. Select the account → Change.
      3. Confirm:
        • Account type: POP3.
        • Incoming mail server: exactly the same value used on the working PCs (if they use a hostname, use the same hostname; if they use the local IP, use that same IP).
      4. Select More Settings → Advanced tab.
      5. Under Server Port Numbers, confirm:
        • Incoming server (POP3) = 995.
        • “This server requires an encrypted connection (SSL/TLS)” (or equivalent) is enabled, and the encryption type matches what is configured on the server.
      6. Click OK, then Test Account Settings and check if both incoming and outgoing tests show green check marks. If not, re-check values against the known-working configuration from the main office.
      These steps align with the guidance to compare port and encryption settings with the provider/server configuration and adjust them if they don’t match.
    2. Confirm the POP3 service and SSL configuration on the server From the context of POP3/IMAP4 in Exchange (or similar POP3 servers):
      • POP3 over SSL typically uses port 995 with mandatory SSL/TLS.
      • If the server is configured for opportunistic TLS (STARTTLS) on port 110 instead of always-SSL on 995, Outlook must be configured accordingly.
      Ensure that:
      • The POP3 server is actually listening on 995 for SSL/TLS, not just accepting a TCP connection.
      • The encryption method expected by the server (SSL/TLS vs STARTTLS vs none) matches what Outlook is set to use.
    3. Compare working vs non-working client configurations On a working PC in the main office:
      1. Open Control Panel → Mail → Email Accounts → Change.
      2. Note the exact values for:
        • Incoming mail server name.
        • Incoming port.
        • Encryption type.
        • Username format.
      3. Replicate these values exactly on the plant-site PC.
      The documentation explicitly recommends checking the incoming server, port, and encryption type against known-good values and updating if different.
    4. Validate that the proxy/CCProxy is not interfering with SSL Even though telnet to port 995 works, that only proves TCP connectivity, not that SSL negotiation succeeds.
      • Check CCProxy rules to ensure it is not intercepting or altering SSL traffic to the mail server’s IP/port 995.
      • If possible, temporarily bypass the proxy for the test PC (direct route to the mail server) and re-test Outlook.
    5. Confirm that messages are kept on the server (optional but recommended) For POP3 users connecting from multiple locations, verify that the POP3 client is configured to keep a copy of messages on the server so that both main office and plant site can access the same mailbox. This is typically controlled in Outlook’s Advanced settings (Leave a copy of messages on the server).

    If, after matching all settings and confirming the POP3/SSL configuration, the error persists only from the plant site, focus on network/SSL inspection at that site (proxy, firewall, or SSL inspection devices) as the likely cause.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.