Notification keeps calling destination server

[jribal]

Hello,
After looking at my pi-hole logs I noticed many calls (1 every 30s) to my notification server without sending a message, all coming from the watchtower container.
I was wondering if it was an expected behavior.

• My messages are correctly send
• Removing the notification parameter gets rid of the server calls
• I looked at DEBUG and TRACE log but nothing shows up.

May  1 09:46:26: query[A] matrix.my.server from 172.18.0.23
May  1 09:46:57: query[A] matrix.my.server from 172.18.0.23
May  1 09:47:27: query[A] matrix.my.server from 172.18.0.23
May  1 09:47:57: query[A] matrix.my.server from 172.18.0.23
May  1 09:48:27: query[A] matrix.my.server from 172.18.0.23