Seems like the mirroring has been in pending for a few days. Is anyone else having these issue?
Use the query SHUTDOWN WITH NOWAIT on the server, then try restarting the services for the server.
Refer link for more information: https://blog.sqlauthority.com/2018/02/09/sql-server-change-pending-state-sql-server-configuration-manager/#:~:text=WORKAROUND%2FSOLUTION,and%20able%20to%20run%20queries.