subdomain blank page ONLY when https

Hi all, maybe it's just been a long day but this one really has me confused: I created subdomains for a new account using the Cpanel tools (everything seems fine) and then installed a multi domain SSL cert (including all subdomains listed individually, not a wildcard cert). All subdomains are functioning properly except when I try to access them with https. When I go to https://subdomain.example.com, nothing shows (blank page with 200 ok response header).

Since the subdomains work properly without ssl, I am assuming the problem is with the cert, but I double-checked with the cert company and everything looks good as far as they can tell. I also ruled out a DNS propagation delay because the unsecure http version of the subdomain works as expected.

The subdomain blank pages are not showing any sign of ssl issues (like https://subdomain.example.com shows the padlock/green text in the address bar). But I can only get a blank page.

Additionally, all but one subdomain are outside of the public_html web root (they all server static content except one "test" subdomain for the developers), and the one subdomain that is set up within public_html definitely is inheriting the .htaccess directives from the parent public_html folder. The others are outside of public_html and share the same ssl problem (blank page only when https) but they have no .htaccess (and I have tested without any .htaccess on the "test" subdomain as well-- same issue). So, I ruled out .htaccess issues.

Any ideas?

 

Sorry I did not mention it right off but this site is on its own dedicated IP address, not the shared main IP of the server.

The ssl cert only covers this domain and its subdomains and was installed via WHM.

 

Yes, my cert for this domain lists the subdomains as SANs and should work on a single dedicated IP. Clearly, I've missed something important in setting this up though.

quietFinn, thanks for the link. I have looked at that documentation, particularly the page with troubleshooting tips for ssl issues, but unfortunately none of the tips applied to my situation.

The main thing to note is that the ssl cert is working for the subdomain (the browser bar shows the correct cert info when I visit the subdomain, the padlock icon displays, and the https text turns green). However the content of the subdomain root directory will not show (and no error is given, it is 200 ok response). So I have no errors to look up... not sure how to troubleshoot...

But I do know it is something wrong with my server configuration. Perhaps I need to edit something in httpd.conf? Maybe the subdomain root folder is not set correctly for ssl?

I expected cpanel to handle that for me when I installed the cert, and I'm hesitant to muck around with config files because any trial and error here is on a live server with dozens of other sites. I am planning to take a look during our off-peak hours tonight, but am not really sure what I'm looking for yet.

Thanks for any ideas/help. It's just hard for me to troubleshoot something with no obvious error messages (I am not a full-time sysadmin or reseller, just a small business using cpanel to host our own sites).

 

quietFinn, I have tested from multiple browsers with cleared cache but not from multiple computers/connections.

cPanelMichael, I only installed the SSL certificate in WHM which applied it to the top level domain that is set up as an account (with the subdomains created via cpanel). Do I need to install the cert some other way? Maybe through Cpanel instead of WHM? Maybe installing via WHM is part of the problem (though I had created the subdomains in Cpanel before I installed the multi domain SSL cert in WHM, so I would hope WHM would take care or any extra steps when there are subdomains involved).

And yes, I have a basic html test page in the subdomain root directory. The test page works fine on an unsecured connection, but when I access it via https, I get a blank page (empty html source, not just my test page with missing elements or broken images... it's a totally blank page with a 200 ok response header). If it was a page not found error or something it would make more sense to me but I can't figure out why it knows which page to serve without the https, but fails when the secure connection is requested.

Thanks for the help so far.

 

cPanelMichael, that worked, I did not realize I needed to install the same SSL cert for each subdomain since www version worked automatically but now see that www was the ONLY subdomain to work automatically with the first install of my multi domain cert on the primary domain.

Thanks!