This article will explain you the cause(s) and solution(s) for this console error.
Error in console:
There was a problem downloading the file [LIBRARYNAME] automatically. Perhaps you have an environment without internet access.
This is normally caused by the location of the library being changed and not being updated in the Forgejar. This usually happens with older modpacks.
Manually download the new Forge libraries and upload them to your server.