This happens quite often, and is really annoying!

this happens quite often, and is really annoying!

Happens so much in Firefox that I just stopped using the extension

This exact issue really got me riled up.
After learning this was a long standing issue I contacted customer support. They suggested I try xyz to see if there was any change. I tried the first suggestiin, but after refusing to spend time trying the other suggestions based on the fact it was a long confirmed issue, they then confirmed they also already had the same results at their end.
If Proton already know its an issue and obviously the company have already tried these suggestions at their end without success, why ask a passing customer to waste their time?
Pretty disappointed when it is a paid service.

I also stopped using it because of this.

This is because ProtonVPN proxy credential is non-persistent which prevents users like me from using the proxy outside the extension (Proxifier, FoxyProxy, etc.). The proxy credential will expire in 10-20mins. But as a consequence, it also means regular users will constantly encounter proxy authentication error which is why you are getting this signin pop-up.

ProtonVPN must switch to persistent proxy credential if they want to fix this bug.

This is why I just stopped using it

also happens not in incognito mode, in Firefox it happens less though

All browser vpn extensions sucks and make this problem, you can to remove and add again this extension for bypass this problem for a while

If you could opt out of the extension and use the app it’s more reliable. If not, then I don’t have any good recommendations

I’ve found it better to just use the local OS application or even better build a WireGuard tunnel and use that, much more reliable than the extension.

But yeah, I ran across this a lot too when using the extension, needs to be addressed.

Ever since I updated the firefox extension about 4 months ago, it has always done this with every launch of the browser.

Sucks!

The previous version I had never bugged out like that.

This is because ProtonVPN proxy credential is non-persistent which prevents users like me from using the proxy outside the extension (Proxifier, FoxyProxy, etc.). The proxy credential will expire in 10-20mins. But as a consequence, it also means regular users will constantly encounter proxy authentication error which is why you are getting this signin pop-up.
ProtonVPN must switch to persistent proxy credential if they want to fix this bug.

The app doesn’t work in Linux, only in some distributions but not in all of them.

Arch for example can install it, but can’t connect.

Oh ok. I haven’t tried on linux. Only on mac and windows

It is possible to set proton using openvpn gui.