I can not navigate through the objects in sql server managemente studio - lock never goes away Whenever I try to navigate through the objects in sql server management studio object explorer I get the error message

Lock request time out period exceeded. (Microsoft SQL Server, error:
1222).

It is impossible to list columns in tables, show code of views and procedures, etc.
It's a SQL Server 2016.
How to look for the cause of this ?
There is a lot of ETL running on the server, can that be the cause ? How to pinpoint the cause ?
Someone's got an open transaction involving the system tables.
Look at sys.dm_tran_locks.
While SSMS is waiting you can examine sys.dm_os_waiting_tasks to see which session it's blocked by.