Please try:
1. cPanel --> MySQL Databases
Current Databases
aaa_jo151 0.00 MB aaa_jo151 X Delete Database
Click on the user
Check ALL PRIVILEGES on the next screen Even if all the other boxes are checked, check "ALL"
Click "Save Changes"
Repeat for all db users
2. If that does not work, your blog/CMS/forum software should have a file named settings or config or configuration (.php or .ini). Open it up and make sure it sets the database host to 'localhost', nothing else. It should be around the other settings for the database.