Having this issue too. Cleared cache/cookies (all time) didn’t help. Uninstalled/reinstalled Brave too, also didn’t work. I can only login to Gmail when using Private tab which is annoying but will do for now until there’s a solution.
The symptom is that every time one tries to log into their Google account, they are presnted with this error.
This is an emergent problem; I’ve been using Brave for months and only started having the issue in the past week.
There are a lot of reports of this on the Google account community help site. So far I don’t see a resolution. There is one post that says that removing the extention “HTTPS everywhere” from eff.org resolved the problem. However, lots of people (including me) don’t use that extension.
Going shields down on the Google accounts site does not solve the problem for me. Just for the heck of it, I also tried disabling each of the individual controls in the shields menu but of course nothing changed.
I’m having same issue, I couldn’t even access youtube. Now i “solved” for youtube trying to delete cookies/data. I am saying “trying” because i can’t even acces to my list of cookies and neither “Delete navigation data” (or somthing similar).