I am running ubuntu server 20.04, osticket 1.15.7

I cannot upload a .eps (ecapsulated postscript) file.
I set it up in tickets, attachment settings with first no restrictions, then manually including .eps as a file time.
If I put the file in a .zip, it uploads fine (and I checked file sizes, that is not it).
I get the infamous undefined 500 error.

Any suggestions?