Recent vPilot issues

For about a month now I have been having terrible issues with vPilot (which used to be working fine). Basically, what happens are:

1. Constant disconnects from the Vatsim servers no matter which server I choose. The error message is: "Network error. The server has failed to respond to the authentication challenge. Disconnected from the network." (I have double checked my Vatsim status and my account is current).

2. Whenever I start vPilot (on the same computer as the sim itself) I get a stutter-fest and peppered with long and short pauses. I usually just fly two aircraft while online (FSL A320 and the PMDG T7). The heavily degraded performance happens with both. If I disconnect from the network I'm back to my usual smooth experience. It's as if vPilot claims a huge chunk of CPU cycles for itself. Never used to be a problem before and I haven't changed anything in my sim. Graphics drivers are the tried and trusted 376.33 version. I tested with the latest drivers but saw no improvement and possibly a bit more of a load on the system.

Any ideas what may be causing this as flying on Vatsim is virtually impossible for me now. IVAO does not seem to have similar issues.

Cheers,

Tony