Registration node dropping from hub random

Hello, the peak radio association is operating about 30 conecting to our Hub (47178) running in the cloud on Vultr with current ASL3. over the pas 3-4 weeks, we have random nodes that will drop from the hub and when I log into those nodes the auto reconnect is attempting to reconnect and it shows “hung up” and auto congestion. Restarting the node does not fix it. If I take the node off line until Allstar link shows that its no longer registered, then restart, it connects again and will last 30mins - 12 hrs and then fail again. I changed our hub to IAX2 registration and disabled HTTP - no luck. still the same. any ideas on how to go about figuring this out?