Most of the mods (on different sites too) can't link to Google & Facebook.
But, if you uninstall your Facebook app, open backup data on Dokkan and link your Dokkan Account after that, you will be able to login to your Facebook using browser.
I do that all the time.
I feel sorry for those who forget to link their accounts and have to re download the 9GB+ game data.
I don't feel mad or anything about this.
I mean, we are all using a MOD.
Of course there's no guarantee of our data will be safe.
It's our fault if we didn't link our data to Facebook after...
I made an account just to comment this.
I'm pretty sure this mod new update is bugged.
Back then, at v5.7.1, i can update it normally. I didn't have to delete my app and installing this mod.
But now, v5.8.0 i got this error.
My next move now is waiting for fixed mod apk, wait for new version...