The problem may be in the SSL implementation itself. You just have to follow a number of steps as outlined below (apologies if you have done all of this already):
Once the server is configured to use an SSL certificate, you need to check that SSL / TLS support is selected for the hosting (I use Plesk and this appears as a checkbox on the server).
Next I add the following lines to the top of the .htaccess file (before the standard WordPress directives):
#SSL redirect
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://yoursite.name/$1 [R=301,L]
# END Redirect SSL
Once this is done, log in to your site and set the WordPress and Site addresses in Settings > General Settings to include the ‘https’ addresses.
At this point WordPress will log you out of the system, so you will need to log in again.
SSL should be working at this point but you may not see the green lock yet in the URL bar. This is because any references to ‘http’ on the page will need to be changed.
There are sites to help with this like https://www.whynopadlock.com/.
I usually just do a search and replace for all http references and replace these with https. You can use the free program https://interconnectit.com/products/search-and-replace-for-wordpress-databases/ while this program works very well, be a little careful when using it by always doing a dry run and checking the suggestions before committing the changes.
[Aside] Once WordPress is working with SSL, don’t forget to update Search Console and Webmaster tools. I also suggest that you resubmit sitemaps to Google and Bing.