Yunohost floating logo thingy doesn't take me back to SSO

Describe the bug

After installing Cryptpad in Yunohost, clicking the Cryptpad tile, and launching the app, I am unable to return to the Yunohost single sign on (SSO) by clicking the floating Yunohost logo thingy.

Clicking should take me to: https://pad.domain.com/yunohost/sso/

Instead I get this in firefox: Blocked Page: An error occurred during a connection to pad.domain.com

This in Chrome: pad.domain.com refused to connect.

Context

• Hardware: *Digital ocean debian droplet
• YunoHost version: 11.0.10.2 (stable)
• I have access to my server: Through SSH | through the webadmin | direct access via keyboard / screen | ...
• Are you in a special context or did you perform some particular tweaking on your YunoHost instance?: no. Unless installing on a subdomain is 'special'. It's on a subdomain 'pad.domain.com'
• Using, or trying to install package version/branch: using 4.12.0~ynh2

Steps to reproduce

Log in as user. Click Cryptpad tile Click YH floating logo see error messages described above manifest...

Expected behavior

Clicking YH floating logo takes you to https://pad.domain.com/yunohost/sso/

Logs

• None

is this issue still valid ?

I haven't updated / upgraded anything on either YH or Cryptpad so 'yes', but if there is something I should do in advance of testing let me know and I'll try. I haven't actually updated either YH or Apps in the past so I might have to figure that out...