Recently another user had trouble logging on to Qobuz in Roon. They were entering a user name rather than an email address. Apparently this worked on the Qobuz app but not for Roon. Is your user name your email address or is it something different? If it’s something different then try entering your email address instead.
I felt certain that you had an I apologise for the IT Crowd image - I just couldn’t help myself! I have now exhausted my limited supply of helpful information. Hopefully others, inducing Support, will have more suggestions.