403 Forbidden error on just 1 ip

hi cloudflare community

I have 2 domains on same CPanel server
few days ago somebody used DDOS Attack on one of my domains so I enabled UnderAttack Mode
now the problem is my 2 domain are connected to each other using rest api

now when I send request from my second domain to my first domain . it will raise 403 error

I tried adding my host ip to Firewall rules as bypass or allow but it didn’t work
by the way, when I pause the cloudflare the problem will be solved

any suggestion ?

Website?

This Link

Is their IP address blocked?

What’s the exact information found in firewall events?