Now it’s working.
i don’t know what exactly was the problem. But finally it added subdomain.mydomain.com on freeflarum which it wasn’t doing earlier.
I also added two CNAMES
One for subdomain to the freeflarum one and subdomain.mydomain.com to the freeflarum one.
I’m still not sure whether that was necessary.
Also it still didn’t work on the network I was on. But works on my mobile network.
So that maybe some dns cache flush issues. But earlier it wasn’t working on any
Leaving this here for others atleast those using Namecheap.
Thanks again Sanguine. I’m going to make a donation of 5 Euros to get the freeflarum off though this is still a forum for my testing with a small group of people. If this takes off I will make a monthly donation.