zeroTier connection problems

Dear team,
It’s been a while since I encountered a problem with ZeroTire and the connections are disconnected and reconnected from time to time. Is it related to the number of connected users or not? we tested the internet connectivity and has no problems and also firewalls are inactive both in server and client
I am using zyclonite/zerotier:1.12.2 self-hosted as docker image in the server and the same version in the clients. Does it have limitation of connected users ? should I purchase it ?
I have 2 networks with 72 devices
I need your urgent help.
Thank you for your support