So there was a similar issue recently However, not sure if and how that got resolved. But let’s follow up on the stuff we saw there.
You can try to reconstruct the command that is shown on the last line. It will become something like /usr/bin/ldns-signzone -e 20230801 -n /etc/nsd/zones/fansdb.xyz.txt... (basically remove the , and the ' from the line, replacing them with spaces.)
Although judging from this line, it will probably complain about line 22 in the fansdb dns file (which you already posted earlier). So take a look at file /etc/nsd/zones/fansdb.xyz.txt and check what line 22 is. Take good care when counting, there are also empty lines which also count. My guess is that it will point at a custom dns entry.