In Setup, Return from Google Allow Leading to an error

Followed all the instructions in the setup three times. Carefully copy and pasted as text all the different codes. Gets to google succesfully after the allow plugin… button , I hit allow on the google site, but when it returns to my site I get “Oops! That page can’t be found.” I have a screen shot but basically everything in the address through =auth is the same as the return code I copied and pasted into google from your setup page, so something about the return code from the & on must be off. I have the full url but hesitant to paste it here.

I have deactivated all other plugins. Only yours is active. I have deleted my cache plugin and every other mail plugin.