I am having the exact same problem as in this linked post.
I can connect to my NFS shares outside of Zerotier but if I try the same mount command with my ZT IP address I get the following error
root@test-rig:~# mount -t nfs 192.168.193.95:/mnt/disks/gregs-data /mnt/user/temp -v
mount.nfs: timeout set for Thu Jul 25 10:14:26 2024
mount.nfs: trying text-based options 'vers=4.2,addr=192.168.193.95,clientaddr=192.168.193.162'
mount.nfs: mount(2): Connection refused
mount.nfs: trying text-based options 'addr=192.168.193.95'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.193.95 prog 100003 vers 3 prot TCP port 2049
mount.nfs: portmap query failed: RPC: Remote system error - Connection refused
mount.nfs: trying text-based options 'vers=4.2,addr=192.168.193.95,clientaddr=192.168.193.162'
mount.nfs: mount(2): Connection refused
mount.nfs: trying text-based options 'addr=192.168.193.95'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.193.95 prog 100003 vers 3 prot TCP port 2049
mount.nfs: portmap query failed: RPC: Remote system error - Connection refused
@nik.v Did you ever get this resolved on your system?