My.homeassistant.io links do not open

I’m new to HA. I’m trying to add integrations etc. using links, which are supposed to open at for example Link to Add-on: dashboard – My Home Assistant (for HACS add-on).
None of these links work. That is, the browser is stuck with the address like the one above, and no page opens.
I can only add stuff from within my HA connection (instance?). I’m sorry if I get some naming wrong, I only installed HA yesterday and have only a vague idea on how things work…

Check the documentation for the My Home Assistant integration, https://www.home-assistant.io/integrations/my/

Then restart Home Assistant.