I think the easiest way to find them may be going to ‘All Site Settings’ and then pasting them into the filter box at the top to pull them up that way.
I think you get a more generic error if the details aren’t right when it tries to do a test run? It might be worth double-checking you have entered all the correct details.
For the other reliant settings, you get a much more descriptive hint if you try and enable one ‘out of order’.
No, can’t enable it just get Sorry, an error has occured, if I try to enable Reply by email first I get the in the screenshot, if I try the other way round same thing.
Making progress now, only seems to work with port 995, just trying to get my head around the Reply by email address, does this have to different from the notification address?