Emails

hello, I never used emails on cwp

yesterday I made a new account for a new website, on the cwp panel I created a mail account and tried to send and receive an email from it.

When I send it, it works... (but it goes in spam) when I try to receive it, I get an error
550 5.1.1 <info@mydomain.com> sorry, no mailbox here by that name. #5.5.1

why does it happen?

can you suggest me a guide to set up my mail in the best possible way? to avoid it goes in spam and so on... where can I learn more about it?

thanks

probably you've wrong MX record.

how can I check? I didn't touch anything

mxtoolbox.com