No connection or ping for 10-20sec every 10-15min from Ubuntu

I have ZT 1.8.10 install on Ubuntu 20.04, and mounted a NFS share from another node. Every 10-15min I suddenly loose connection, eventhough ZT claims it is online. I can not ping or reach any other nodes (internet is fine on the host) for 10-20seconds, and then everything is back again. I don’t see anything in dmesg or in the zerotier-one service status.

Clearly it is a zerotier issue, as host network is fine. Can I turn on some zerotier debug logging?

> date                                                                                                             
Wed 01 Jun 2022 09:18:19 AM CEST

> ping 192.168.195.20                                                                                                  PING 192.168.195.20 (192.168.195.20) 56(84) bytes of data.
From 192.168.195.70 icmp_seq=1 Destination Host Unreachable
From 192.168.195.70 icmp_seq=2 Destination Host Unreachable

]> ping 192.168.195.2                                                                                               
PING 192.168.195.2 (192.168.195.2) 56(84) bytes of data.
From 192.168.195.70 icmp_seq=1 Destination Host Unreachable

> sudo zerotier-cli status                                                                                         (base) 
200 info ************ 1.8.10 ONLINE
> date                                                                                                             (base) 
Wed 01 Jun 2022 09:21:38 AM CEST

> ping 192.168.195.20                                                                                                  (base) 
PING 192.168.195.20 (192.168.195.20) 56(84) bytes of data.
64 bytes from 192.168.195.20: icmp_seq=1 ttl=64 time=13.1 ms
64 bytes from 192.168.195.20: icmp_seq=2 ttl=64 time=12.0 ms

> ping 192.168.195.2                                                                                                   (base) 
PING 192.168.195.2 (192.168.195.2) 56(84) bytes of data.
64 bytes from 192.168.195.2: icmp_seq=1 ttl=64 time=28.4 ms
64 bytes from 192.168.195.2: icmp_seq=2 ttl=64 time=11.7 ms