Spark mail app won't let me add a second account, iCloud to my Mac

Any Spark mail users out there? Every time I try - I get the app-specific password from Apple - but nothing happens. I have a 365 account and want to add my iCloud account. I have successfully added them to both iPhone and iPad but can’t add to my Mac. I have deleted it and re-installed. No luck.

Readdle are not responding.

Any ideas?

OS 10.15.5
MacBook Pro, MacBook Pro (Retina, 13-inch, Mid 2014)
Spark 2.8.1