I am the same issue "Unable to edit your database with the provided credentials.
Please make sure the connection user has write access to this database. (You may need to upload the connection to server if you have made changes recently).
I've also followed the instructions above...
1. Check connection to make sure the username and password is correction
2. Click select button when making a connection to make sure you can reach your server's database
3. Test connection :: successfully connected
4. Go to my setup options>>servers>>select remote and testing boxes
5. Open Power CMS App in Dreaweaver with content selected
6. Create a new "content location"
7. create a new "Conent Area" name
8. Click finish
9. Auto creates connection on both local and server
10. Error message shows up!
What do I do next?