Issue when input with ligand

[VGPReys]

Describe the bug

Issue when running body-restraints on a PDB file containing ligands (haddock3-restraints restrain-bodies <ligand.pdb>).

To Reproduce

Copy from the forum:

I tried to launch a few protein-small ligand runs in the HADDOCK3 
Server, but they never launched. No error message appeared on screen, 
either.

Using Chrome’s Developer Tools, I found a few errors in the log:
- Failed to load resource: the server responded with a status of 500 (Internal Server Error)
     useSafeFile-7kFfkN-X.js:17 Calculating restraints of bodies failed,  treating like no restraints where found Internal Server Error (useSafeFile-7kFfkN-X.js:17)
- Failed to load resource: the server responded with a status of 422 (Unprocessable Entity)
- Uncaught (in promise) Error: A listener indicated an asynchronous response by returning true, but the message channel closed before a response was received

Expected behavior

No issues when submitting a ligand

Additional context

Identified by an external user: https://ask.bioexcel.eu/t/haddock3-webserver-issue-when-launching-protein-ligand-docking-run/5919/2