TFAR .pbo Not Signed Error

If you are receiving an error that looks like the attached image, try deleting the contents of your TFAR folder in !workshop folder but not the folder itself. After that, try repairing the mod in your launcher. This may fix the issue. Repairing without deleting, deleting entirely, unsubscribing and subscribing, etc. did not work in this case. Only once the contents were deleted and the mod was repaired did it allow the client in to the server.

The error reads: " are not signed by a key accepted by this server. To play on this server, remove listed files or install additional accepted keys.