I was playing on my server perfectly fine last night, I could load it up no problem.
Now today when I started my server every time it stops and a message in yellow says:
[BetterFps Update Checker/WARN] [BetterFps]: Could not check for updates: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 2 column 2 path $
I have not changed anything on my computer since I played last night, please let me know if you can help me out with this at all.

Will need the full crash report (if there is one) or the latest log. That line does not indicate any potential issue of why the server won't work