You’ll probably need to have a look at the browser javascript Console to see whether there are any errors displayed. Also check the web server log at your hosting for any errors.
To prevent any confusion, I’m not iThemes.
I found and fixed the issue, thanks to your suggestion to review the web server log.
Several errors in the web server log like these:
2020-06-14 17:34:20.538515 [INFO] [27919] [108.162.246.204:61270#APVH_[domain_omitted]:443] [ACL] Access to context [/] is denied!
2020-06-14 17:34:20.481196 [INFO] [27918] [108.162.221.163:19942#APVH_[domain_omitted]:443] [ACL] Access to context [/] is denied!
2020-06-14 17:34:21.215412 [INFO] [27921] [108.162.221.181:28080#APVH_[domain_omitted]:443] [ACL] Access to context [/] is denied!
2020-06-14 17:34:21.412857 [INFO] [27921] [108.162.221.115:17680#APVH_[domain_omitted]:443] [ACL] Access to context [/] is denied!
2020-06-14 17:34:21.862605 [INFO] [27921] [108.162.221.211:13262#APVH_[domain_omitted]:443] [ACL] Access to context [/] is denied!
2020-06-14 17:34:22.111123 [INFO] [27918] [108.162.221.247:61252#APVH_[domain_omitted]:443] [ACL] Access to context [/] is denied!
All originating from 108.162.*.* which turned out to be Cloudflare, my CDN provider – I had unintentionally added 108.162.*.* in my blacklist which not only completely hosed iThemes Security but also the reason for a multitude of 403 forbidden errors on a multiple # of my sites but also weird issues I was noticing with the themes on my WP sites that I had no idea was being caused by this block.
Thanks for the idea – lesson learned… don’t blacklist your own CDN. 🙂
Regards,
Terry