From ArcMap I published a WMS to ArcGIS Server (version 10.5.1). Using ArcGIS Server Manager I secured my WMS by restricting the service to a role. I also created a user having this role. Using the REST API I’m able to log in with the username and password of this user. This – in my opinion – indicates that the authentication itself works.
Accessing my secured WMS by using FME, QGIS, ArcMap or using a browser, however, was not possible. However, I was able to access other secured WMS, thus the problem has to be my WMS. I can also access my WMS as long as it is not secured, thus this is not the problem either.
Some more information
Any ideas what could be wrong?
Thanks for your help in advance. Cheers
The issue here is likely that you've configured your service to require ArcGIS Token-based authentication, but tokens aren't really part of the OGC spec. Most of the clients you mention are likely expecting the server to support basic or NTLM authentication.