This problem can be the result of several events.
1. Please check if the database connection is properly configured. More details can be found HERE.
2. make sure that all your services are paid for and that the hosting package you have is appropriate for the amount of data you store
3. it may also happen that the user of your database has exceeded the limits set for our servers. Granting a lock is a signal to optimize INSERT and SELECT queries in a given database. Setting a new user password (CLICK HERE) Should automatically remove the lock, but please - optimize database queries.