Hi Plasmi
I tried all other suggestions i.e. shields/cookies etc. All failed. I love Brave Browser but was logging in to Opera (which I hate!) to access gmail. Just by chance I right clicked on the Brave icon on my home screen (PC) and then “Troubleshoot Compatibility”. It ran a check and found issues (it opted for Windows 8). I clicked on Fix Issues and saved. HALLELUIAH - IT WORKED!!! Has been working perfectly ever since. Good luck - it is worth a try.