Improve the Connections Wizard
Adding Connections is a little bit buggy. It tells me it has not worked although it added it to the list and for my Microsoft OneDrive for Business I cannot make it work.
Sorry for your troubles!
Just for some additional clarity around the issues you're facing - are ALL of the Connection creations erring even though they appear in the Connections list, and no Connections can be used in the Designer? Or is it specific to a few Connectors that you are interested in using?
For Microsoft OneDrive for Business - Are you seeing any errors during the process? At what point are you seeing the failure?