This is something we experienced for quite a while with several versions of the Notes client on different systems: the Notes client randomly tries to access known servers in the environment (aka servers with a connection document in the names.nsf).
I never understood the strategy behind the client trying to access a "server A" when this isn't even the mail server of the used location after login, especially when the ID is not even allowed on "server A". Ok, I live with that for decades and sometimes it helps to nuke the $Saved... fields in the location document(s). But this is another story.
The story I want to tell with this post is the following: we randomly see Notes trying to access a "server X" where the currently used notes ID (defined in the location being used) is not cross-certified.
This is a companion discussion topic for the original entry at https://oliverbusse.notesx.net/hp.nsf/blogpost.xsp?documentId=243E