Things are so complicated and anoying in DNN!! , I'm really getting sick and tired of it!  Here is just a standard story of how things get super frustrating for a simple job (note that I am using this CMS for more than 8 years now)

We wanted to use Lets Encrypt for a SSL Certificate.

1) Of course DNN has nothing built-in to Let's Encrypt and there is no official documentation about it so we start following this blog post: 

https://justinacton.com/2016/08/12/free-ssl-cert-for-dnn-using-lets-encrypt/

2) Since we do not want to break all 'user friendly' URL's we needed to install a module: "Url management".  The module is not core/official, is on Codeplex (which is shutting down) and is an old version which is saying to support "DNN 7.2+"  (Hello, we are on DNN9 nowadays!).
Without any other option, I'm trying to install it.

3) For this module to get started I had to create an Admin page and add the module to it.  (I wonder why this is not done by default installation but ok..).
In DNN 9.0.2 with the new 'Perona bar' I am NOT able to create a new admin page but after Google'ing around I found I could still use ../Admin to go to the old interface and add it form there.

4) Now I needed to go to this page and Add the URL management module to it.  Unfortunatelly the 'Add Module' button doesn't work.  After searching the Forums it seems there might be another module or javascript blocking this.  However,  my error is: 

Uncaught TypeError: Cannot read property 'data' of null

    at Object.onClick (AddModule.js?cdv=591:17)

    at /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:182

    at getMenuLoader (/DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:74)

    at /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:180

    at /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:157

    at Object.success (/DesktopModules/admin/Dnn.EditBar/scripts/sf.js?cdv=591:50)

    at j (jquery.js?cdv=591:2)

    at Object.fireWith [as resolveWith] (jquery.js?cdv=591:2)

    at x (jquery.js?cdv=591:4)

    at XMLHttpRequest.<anonymous> (jquery.js?cdv=591:4)

onClick @ AddModule.js?cdv=591:17

(anonymous) @ /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:182

getMenuLoader @ /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:74

(anonymous) @ /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:180

(anonymous) @ /DesktopModules/admin/Dnn.EditBar/scripts/main.js?cdv=591:157

success @ /DesktopModules/admin/Dnn.EditBar/scripts/sf.js?cdv=591:50

j @ jquery.js?cdv=591:2

fireWith @ jquery.js?cdv=591:2

x @ jquery.js?cdv=591:4

(anonymous) @ jquery.js?cdv=591:4

Where was I ?   Oh.. yeah.. All I wanted to do was installing a certificate and then run into all this trouble.  It's not just this time but for almost everything you want to do you run into trouble of:  Old modules..  Failing upgrades.. Paying a lot for module-support-refreshments after you upgraded the core network and modules stopped working.  ApplicationPools and ASP.NET version hassle... pffff

The advantages of Let's encrypt are:

- Automatic Renewal
- Free for unlimited domains (So once I set it up, I can use it for 100+ portals if I want)

Let's Encrypt becomes quite usual these days (since StartSSL is not trusted by Apple and Google anymore).

You are right that I can switch the site to 'humanfriendly', then do the request or renewal and then switch it back to 'advanced'.  However, when using the 'URL Management' module, you can skip this because the module is a workarround for that situation.

You are righjt that you need an special answer file but, as far as I know, the script takes care of that.

For the moment I am still having the problem that I can't Add a module to a Page since the upgrade to DNN9.0.2. (see above error)