It would seem that WP 4.6 has broken the integration plugin, I have a report into the crew to look at it. Do not upgrade unless you think it will not affect you the error is ... Code: PHP Fatal error: Call to a member function query() on null in /home/.../public_html/amember/library/Am/Lite.php on line 581
Doh! Wish I had seen your post before I upgraded to WP 4.6 and then upgraded to Amember 5.1.3 last night. In any case, thanks for letting us know.
With help form the crew reduced the number of errors plugin "Uptime Robot Plugin for Wordpress" if installed with the current WP causes issues. Still having random failures, investigating them will advise when I find the cause ... it's all fun.
Has anyone else tried to upgrade to Wordpress 4.6 - especially those without this plugin? If so, have you faced any errors with that? Thanks.
I contacted the author of the plugin, he has released a fixed version. All working now (famous last words).