How Do I Setup 'Let's Encrypt' To Work With My WPMS Subdirectories Install?


– I have a WPMS install using subdirectories.

– I am using Siteground as my host provider, which they offer ‘Let’s Encrypt’ setup.

– I’ve already enabled that on my domain and it works fine… only when you go to the primary domain. It doesn’t seem to be working when you attempt to visit of the sites i create within my WPMS install. However,…

– When I attempt to login to one of the other sites (from its respective wp-admin login page), I enter my login and password and hit the ‘Log In’ button. Instead of logging me in, it simply reloads the same page and clears my fields.

– When I click on ‘Lost your password’, I get this error message:

This site can’t provide a secure connection sent an invalid response.

Try running Windows Network Diagnostics.


After researching the ability to use ‘Let’s Encrypt’ with WPMS, I believe their website states that it doesn’t support WPMS (yet) when using subdomains. However, if using subdirectories, it should work fine. Ultimately, this is what I’m attempting to do.

If I can get assistance in this, I’d greatly appreciate it. Thanks in advance.


– Sammy

  • Denitsa
    • WordPress Warrior

    Hello Sammy,

    I hope you are having a fantastic day and thanks for posting here!

    Do you have mapped domains too?

    Will you please grant support access from the dashboard plugin so we can take a closer look?

    This could be done via Dashboard – WPMU DEV -> Support -> Support Access -> Grant Access or by following this guide here:

    Here are some threads that might prove helpful for your case if you want to take a look meanwhile:

    Let me know once you have that support access open!

    All the best,


  • Sammy
    • Site Builder, Child of Zeus

    Hi Denitsa,

    Thanks for the info. My apologies, though. I failed to mention one other detail. I’d like to use the same SSL. ????


    PS: Siteground automatically renews each Let’s Encrypt SSL install, which is great, considering they expire and must be renewed after a certain amount of time.

  • Lindeni Mahlalela
    • Recruit

    Hello Sammy.

    I hope you are doing great today. I am sorry you are having problems with your setup and I hope we work together and maybe we can come up with a solution.

    To my experience with Let’s Encrypt, you can use it without problems on a sub directory install of WordPress Multisite. I have such a setup I use as a development and testing environment and have never had issues since I created it. You can use the same SSL certificate for an unlimited number of sub-directory based sites, this is because the host treats those sub-sites as sub-folders of the main site.

    When it comes to sub domain install, Let’s Encrypt does not currently support wild card subdomains which means you cannot cover all your sub domains with the same SSL certificate. If you really need to use sub domains, then you have to generate the certificates manually specifying each sub domain in the list. Each SSL sertificate can have up to 100 domains in total (sub domains included). So that means you can have,, etc, this is a very long and tiresome process.

    If the host automatically includes sub domains on the main SSL, then you can create sub domains for each subsite and point it to the root folder of the multi site install. This way the host will be able to add and renew the certificates for all the sub domains. The trick is that you cannot have * in your SSL.

    You shouldn’t go through all that trouble with sub directory install.

    Instead of logging me in, it simply reloads the same page and clears my fields.

    With regards to the login form, I was unable to reproduce this. I created myself a user account with “Subscriber” role and was able to login to all sites without issues. I then changed the same account to make it “administrator” and I was able to login again without issues. Would you please verify if you are still having the same issue.

    I hope all this makes sense and helps you with your setup.

    Please enjoy the rest of your day.



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