I have been using it for years and it’s very random. Sometimes when it is turned on, home Assistant would not work. And other times it is completely fine. When I look at the logs, my internal URL for assistant is not being blocked so there is nothing I can unblock.
What’s s more IM blocked both using the companion FM using the mobile Chrome browser.
Any ideas?
I never used blokada and only know about it because of negative feedback and the fact it was kicked out of F-Droid. As you use the last open source version (5) while the devs already moved on selling arguable cloud based blocking with version 6 I don’t really expect (m)any more bug fixes for version 5 (last release from may). 
Long story short: Switch to another app which is more reliable and actively maintained? Or you might just be happy setting a private dns in your phone which includes ad/track-blocking like blahdns.com or dns.brahma.world 
I tried setting a private dns to dot-sg.blahdns.com but it stops my HA too.
I use a custom domain name for my HA server, is that the issue?
Is it a “public” domain?
Yes it is. But I also have a pihole on my wifi to deal with it.
Maybe that’s the issue? I need to use pihole on wifi and one of these when on mobile data? How would I do that?