we do not get the owa add-in working. (Outlook Plugin work fine)
Error: initialization Failed
ErrorMessage: The remote server returned an error: (401) Unauthorized.
1) Exchange 2019 CU4 OnPrem
All Servers behind Network Loadbalancer. Virtual Directorys External and Internal URL like (mail.contoso.com)
We did not find any helpfull hint in the Exchange OWA EWS HTTPProxy EWSProxy or IIS Logs
2) Enterprise Vail 12.5.1 Cluster
Did anyone get the OWA Addin running?
have you seen this one?
Personally haven't had this one so far. We managed to sort out some topics in the past or at least got closer to the root cause by following this approach here when troubleshooting issues like this, though I am not completely certain this still completely applies to Exchange 2019:
please excuse the missing reply.
Are you able to contact Veritas technical support to discuss the topic? They might be able to help you understanding if some kind of workaround can be applied. I believe due to your configuration the internal communication between the servers is broken at some point. I thought I'd remember a similar situation from the past but are currently not able to locate more details. Whenever I find something I'll let you know.