Have you ever witnessed this happening on a local machine or have you only seen the issue when running on a VM? I ask this because it's going to be hard to suggest a fix for the issue unless someone has already run into that specific problem. Do you have any info on whether the event logs show anything or the errors that show up in the session logs?
The first thing I would try if I can't find any info from the logs is to put retry logic around that part of the process. If it is timing out, then it hopefully throws an error that you can catch and retry. I'd be curious if on the 2nd or 3rd attempt whether it succeeds OR whether it fails multiple times in a row any time that it fails once. Does that make sense?
Also, when you say that you use the Excel VBO to open Excel 365, are you referring to Create Instance, Open Workbook, or something like that?
If you're doing 'Open Workbook' without 'Create Instance', try using 'Create Instance' first and then use 'Open Workbook'. Maybe Excel is having difficulty opening the file.
Respectfully,
Dave
Dave Morris, 3Ci at Southern Company