Apex domains cannot have CNAME records.
Question and response
Question
dig tawk.email. NS
Answer
tawk.email. 1 NS pat.ns.cloudflare.com.
tawk.email. 1 NS edward.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0