Unable to upload xlsx, zip or svg files - RStudio server gives "unexpected response from server"

Hi All,

I saw several similar posts but no real solution.
Whenever I try to upload a file during an RStudio Server session the system gives me "unexpected response from server". The bizarre thing is that I get this error only when I want to upload an excel (.xlsx), zip files or .svg file.

Since most of my raw data is in .xlsx format this is an issue.

Anybody knows a solution?

Regards,
Michael