Domain email addresses don't work.
I've created a couple emails for my website any time someone tries to email me via those addresses they get a response saying "Google tried to deliver your message, but it was rejected by the server for the recipient domain contemporarysuccess.com by aspmx.l.google.com. [2607:f8b0:4001:c03::1a]." The message also says that the emails don't exist despite the fact that I'm able to login to webmail and send messages using the accounts. Any help is much appreciated!
As the messages are being sent directly to Google's servers, the accounts would need to be created there and not within your hosting account here.
Creating the email accounts on your hosting account will not affect your mail being received at all because the mail never reaches your account with us when your mail is pointing to Google.