The other day I made two new projects, successfully linked the first project to the first sql db no problems.
Today I did update to 2.5.5 - Not sure if they are related but now I cannot establish a simple connection in the second project to the second db. I see one other recent ticket with the similar output: Problem with Target logic for FTP, local folder mysql, remote mysql, online mysql
Nevermind I have found the issue! My target was incorrect but had let me save and even upload. Using an alias and sub-dir in apache the port and path needed to be defined within the Web Server url on the Target.