[tor-relays] Relay stuck at Bootstrapped 0%

[Paul]

I am running two relays on debian (one on Raspian 9 and one on Debian 9)
and one of them for over three months now.

Some time ago the older one started to loop at startup.

I reinstalled tor and it worked for some time only to loop again.

The last notices entry looks like this "Feb 16 19:36:14.000 [notice]
Bootstrapped 0%: Starting" and the next is "Feb 16 19:42:08.000 [notice]
Tor 0.2.9.14 (git-a211f886ad759cab) opening log file." then it tells
about opening the listeners and parsing the GEOIP files, then my relay
identity and the bootstrapped 0% entry again (left some informational
entries out).

The debug log looks like it is getting descriptors and stuff correctly.

What could be the problem?