MySql Strange Runs Of Command Denied Errors

I have an intermittent problem with a MySql database.

Everyt开发者_运维知识库hing runs just fine for long periods of time, but then we suddenly get a run of errors being logged such as this:

MySql.Data.MySqlClient.MySqlException: UPDATE command denied to user 'user'@'ip.add.ress' for table 'tblTable'

The user being reported is the correct user. The same user works just fine almost all the time, but when we get this error we get a load all at once.

I know this is vague, but I have checked that the permissions exist, and indeed the same code, using the same user works almost all the time.

Confirmation: We are not restricting access by IP - it's just a user name and password.

Just to close this one out. We solved this issue by granting the same user elevated permissions (i.e. against the MySQL instance as well as the specific database).