Overview
Sometimes when previewing files in M-Files Classic or New Web connections the 500 Internal Server Error (in Classic Web) or Preview unavailable for this file (in New Web) texts appears to the M-Files preview section in the browser.
Solution
To solve this, one possibility is to check that Preview is enabled. That configuration can be found from Advanced Vault Settings -> File Previews -> Viewer Files -> Enabled. Change Enabled to value Yes.
Other possible solutions for preview not available can be found from this support article:
Cannot Preview Large Files in Web (Max Preview Size) (site.com)
