What does my error mean?

1. Trying to update a mod and it says RateLimitExceeded/AccountLoginDeniedThrottle.
2. When updating it says System.IO.FileNotFoundException

Trying to update a mod and it says RateLimitExceeded/AccountLoginDeniedThrottle

Short answer you may have typed in your Username/Password in wrong, if not.
Client is faulted and cannot be used: Error code: RateLimitExceeded Warning: The logon may have failed due to expired sentry-data. If you are sure that the provided username and password are correct, consider deleting the token file for the user "" in the sentries directory.C:\Users\jup\AppData\Local\FoxliCorp.\FASTER_StrongName_X\1.9.5.1\sentries

When updating it says System.IO.FileNotFoundException

Make sure you have stopped your servers first.