Difference Outlook vs curl

Question

We want to change from F5 LB to HAProxy and pretty much all services are switched already. As long as we have Exchange 2016 behind the F5 everything works just fine. As soon as we switch it over to HAProxy we experience "401 Unauthorized" errors and Outlook is permanently asking for credentials without getting a connection. The MS Connection test is giving us a hint to autodiscover.xml.

We tried to use a curl command to send the post to Exchange/autodiscover/autodiscover.xml and we get a proper authorization here and the corresponding XML. What does Outlook do different from what a curl command does?

Answer 1

Hi @Daniel T ，

As soon as we switch it over to HAProxy we experience "401 Unauthorized" errors and Outlook is permanently asking for credentials without getting a connection. The MS Connection test is giving us a hint to autodiscover.xml.

Regarding your concern about the difference between Outlook and a curl command, I tried searching a lot but hardly find any documentation stating this explictly. Given this, could you remove all personal information involved and then share the hint returned in the MS Connection test so that we can see if we can search further on this?

By the way, does everything work fine when HAProxy is bypassed? If this is the case, I'd suggest contacting the support for HAProxy as well to to check if there are other users who have encountered this situation and whether there's recommended solution.

---

If an Answer is helpful, please click "Accept Answer" and upvote it.
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.