Migration from old host to new host v. 1.4

Hi guys,
I am new to the forum (because PunBB works so well I have never had the need to come here and ask for help).

I have been forced to move my PunBB (vers.1.4) forum from the host where it was installed to a new host.

This is what I did:
1) on the old host: dump the mysql database in PhPMyAdmin
2) on the old host: download all files to a local desktop folder via FTP
3) on the new host: re-upload all the files, including punbb folder and files, in the public_html folder (note DOMAIN HAS NOT CHANGED)
4) upload mysql database in new host PhPMyAdmin, after creating a new database dedicated to this

Unfortunately here is where I am lost because doing the above the PunBB forum doesn't work anymore: I get this error msg when I try to access the index.php page (homepage to the forum):

Sorry! The page could not be loaded.

Unable to connect to MySQL and select database.
MySQL reported: Access denied for user 'xxxxxxx_punb434'@'localhost' (using password: YES)

Is there any step by step guide on how to do this? Or any suggestion to fix my error/s in doing the above procedure?