Zero trust with cname not working

I have the following scenario, with 2 different domains (all in cloudlfare)

Cloudflare Tunnel at notify(dot)domainA(dot)com works ok and hits the origin server nicely.

Later i added notify(dot)domainB(dot)com that is a cname to notify(dot)domainA(dot)com. It does not work, but if i modify notify on domainA to be a A record instead of a zero trust tunnel, it works.

The images illustrates better the problem

How can i solve since i want it to be a tunnel and be able to be called from booth domains.

Thanks in advance