Hi
First, there's a likely Joomla configuration issue: the detected server address is http, while your site is entirely https
This is happening because your Joomla SEF system plugin is misconfigured. It still says that your site is http:
You should change that to https, or better: just empty the field, as Joomla should detect your address correctly anyway. I did not change it myself as don't know the reason it's been set like that.
Now as for our actual problem, it looks like your web server is blocking 4SEO:
As you can see on the screenshot, this is not Joomla or an error blocking the request but indeed your webserver. This can be the web server itself, or it can be a rule in your .htaccess file.
As you are using AdminTools, the first place to look is the .htaccess file changes that it made. Another option is to directly talk to your hosting company to find out which rule was triggered that's blocking our access to the site. Currently 4SEO is allowed to read data from the site but not make any change (to its own data).
Best regards
Yannick Gaultier
weeblr.com / @weeblr