Hi.
I have social login working on my site for Google with no problems. But with X, no matter what I try, the process ends with the user looking at a blank screen (except for a zero in the upper left-hand corner) and the address bar showing:
https://mydomain.com/wp-admin/admin-ajax.php?action=wpd_login_callback&state=XXX&code=YYY
where XXX is a long-ish hex sequence and YYY is an even longer alphanumeric sequence.
It seems that the X authorization itself may be working. The X login screen comes up as expected (if the user isn't already logged into X) and then the authorization screen comes up with the correct app. There's no error message from X that I can see.
I already searched this forum and tried various other suggestions: I triple checked the callback URL, the API key and secret, and the app settings. I cleared the server and browser caches. I turned off security plugins (although I don't think they're interfering, since the Google social login works just fine).
Any help would be greatly appreciated. Thanks.