Server keeps crashing

Me and my friends are playing on a forge server with only a few mods. It has randomly started crashing and the only thing it says in the console is:

"[19:48:23] [Server Watchdog/FATAL]: A single server tick took 60.00 seconds (should be max 0.05)

[19:48:23] [Server Watchdog/FATAL]: Considering it to be crashed, server will forcibly shutdown.

"

Can someone tell me whats wrong please?