Can you confirm in section 22 "https://login.microsoftonline.com/extSTS.srf [<-- You should be prompted to
download the file.]" - that the file should be downloadable? (I've tried from a variety of different machines but get the same experience)
When i run the psexec test I get a webpage that says
"Sorry, but we’re having trouble with signing you in.
AADSTS900561: The endpoint only accepts POST requests. Received a GET request."
I'm seeing errors in outlook (onprem) to 365 mailbox f/b lookups that state
"<MessageText>Failed to communicate with https://login.microsoftonline.com/extSTS.srf."
so it seems a very similar error but i'm struggling to troubleshoot further.
Thanks for any pointers.