It’s not necessary. The logs are telling you that the tor IP blocked by the blocklist is what IPFire attempted to connect to:
|19:15:06|ntpdate[26682]:|sendto(tor.nocabal.de): Operation not permitted|
|19:15:04|ntpdate[26682]:|sendto(tor.nocabal.de): Operation not permitted|
|19:15:02|ntpdate[26682]:|sendto(tor.nocabal.de): Operation not permitted|
|19:15:00|ntpdate[26682]:|sendto(tor.nocabal.de): Operation not permitted|
178.63.52.50 is tor.nocabal.de. IPFire tried 4 times, gave up and changed to a server that allowed the sync to happen (79.133.44.140 ). Clearly, servers included in the tor blocklist are also part of IPFire NTP pool. I think you can ignore the issue. The block list will prevent the time sync for few seconds, until another member of the pool is connected and the sync will proceed normally. This will only have the consequence of spamming a bit your logs. I think you can live with that.