The server has updated to 5.1.1, but there are a few known issues:
1. Gyms are still currently broken (Working on getting a fix from the Pixelmon Devs)
2. Leveling past 100 is currently disabled as well as using custom candies. We are working on getting a fix for this and hope to have it back up tonight.
Sorry for any inconvenience this may cause, we hope to get these issues fixed soon.