Very kind of you that you help us and even perform tests to do this!
KevC: If the database name is wrong, you don't get that error. You get one saying unknown database, not access denied.
At least in our case you get the error I mentioned, because we wrote a separate script (outside phpbb) which tries to connect to the database with an incorrect database name (and everything else ok)
$link = mysql_connect ($server, $username, $password) is then ok as expected,
mysql_select_db($databasename, $link) throws the error
Access denied for user '******'@'10.3*****' to database 'wrong DB-name'
I agree with you that the error is strange, you would expect the error you mentioned: unknown database
We contacted our hosting provider about this.
You seem to have a script which tests phpbb-database names, would you be so kind to test a
name with an underscore _ sign in it?
Besides that we got the error when we were running an update (install/database_update.php). Might that give other results?
(because this file is not a part of an operational phpbb-forum)
The update version we use is 3.1.5. (I saw that 3.1.6. became available last weekend, please let us know if we should try that one to update our 3.0.14 forum)