Email step error

when is send email , i got this error. please tell me complete setup of mx record in cloudflare.

There was a temporary problem delivering your message to . Gmail will retry for 20 more hours. You’ll be notified if the delivery fails permanently.

Depends who your registrar is?
If you’ve already parked the domain with us?
What email solution are you using i.e. Migadu, Zoho, ImprovMX?