I'm a user of some popular web service and I use 3rd-party client for the service. The client is actually abandonware for more than 3 or 4 years, but it's probably the most convenient client ever for that service, so I don't want to switch to another client (at least I want to believe I won't switch). Recently I logged out in the client hence I had to log in again. But, since my account at that service was authenticated by Google, I cannot authenticate now because Google blocks the authentication (as far as I understand, because the authentication is not in a browser):
This user-agent is not permitted to make OAuth authorisation request to Google as it is classified as an embedded user-agent (also known as a web-view). Per our policy, only browsers are permitted to make authorisation requests to Google. We offer several libraries and samples for native apps to perform authorisation request in browser.
As far as I know, this restriction was introduced back in 2016 and since then I had a valid authentication token not even knowing that I won't be able to authenticate anymore. So I got stuck. Nevertheless, the official client shows an authentication popup where I can choose my Google account, that's as far as I understand is not a web-view.
Is there any solution to authenticate as a Google user via a web-view now? (If it's impossible, I can migrate from my Google-authenticated account to a new one, featured by the service, but it won't be that easy.) Your help and advice are highly appreciated. Thanks in advance!