Google OAuth fails to fill in SMTP info

Hi,

Today I tried to set up email alerts to work with Google via OAuth on my RN102 (Firmware 6.10.3). I complete the OAuth pop-up processes, but am returned to a screen with User, Password and From settings filled out as I expect, but with nothing for the SMTP Server and SMTP port settings, and an error showing for the blank SMTP Server. See screenshot:

This seems identical to the earlier thread "Gmail oAuth does not work properly" by mattbodman, which was left unresolved. As suggested there I've cleared and repeated the process several times, with 3 browsers (Opera, Edge & Chrome), always with the same results. No browser appears to block any pop-up. Each attempt adds just two entries to the logs:

System: Alert contact information was saved.
System: Alert settings are updated.

My Google account shows that the ReadyNAS Email Notification application has been successfully authorised.

Can anyone help? In case it's relevant, I'm connecting to an account from my own domain managed with Google Apps.

What puzzles me is the following screen, which is the last pop-up I see before returning to the NAS admin page:

I've little understanding of the details of OAuth, but this confuses me for two reasons:

• I've never used the Cloud Storage service (it's switched off on my NAS, and, though I seem to have an account there, my NAS is not registered with it, so why's it (trying) to get involved?);
• the URL that I've obscured is my internal network URL for my NAS (and is unroutable from outside my network) so I doubt Cloud Storage would be able to redirect anything to it.

Could either of those thoughts be relevant?

Thanks in advance,

Brian