Can you provide more info? What domain are you trying to connect? Did you add the TXT/CNAME records as instructed?

my cpanel does not allow to add @ in name for cname record

I’d recommend migrating to Cloudflare’s DNS as they support CNAME flattening (using a CNAME record on a root domain).

got this message after propagation

You need to add TXT records.

already added

What domain are you trying to add?

how to install SSL ?

You’d need to correctly add the CNAME/TXT records as instructed.

i have completely connected domain to cloudflare , is that possible to connect Mail Server i use webmail in cpanel ?

You need to check Webmail’s documentation for that.