When using mysqldump or backing up an account, the following error is returned.
mysqldump: Got error: 1356: "View '$view' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them" when using LOCK TABLES
mysqldump is reporting that the MySQL view is malformed or corrupt. This can happen due to changes in the database structure, removal of databases, or an incorrect definer being set.
If the issue is with a "sys" view, this third-party article has repair instructions that can be reviewed by a database administrator.
Otherwise, the referenced view will need to be repaired or removed.