I didn't receive the 2FA Code
Step 1: Check out the Junk Mail Folder
In many cases, the email may be marked an e-mail suspicious and move it to the junk e-mail folder. Therefore, if the e-mail is sent multiple times from an address but you haven't received it in your inbox, then possibility is it has been moved to the junk mail folder. So the first step is to check this folder to ensure if the application is marking mail from the sender as spam. May be you get the solution in first step!
Step 2: Confirm Integration of Virus-Scanner
If a virus scanner or anti-spam tool is integrated with your email client, then possibility is it is causing hindrance in receiving emails. To test if the scanner is causing the problem, disable it for some time and then ask the sender to send the mail again. If it works that means you know what the problem is.
If you have installed some third party anti-spam tool, then check its documentation to find out what is actually does when it considers a mail as spam and find out how its integration with email client can be disabled.
Step 3: Check Email Arrival on Other computer/phones
If the same account is configured on multiple devices like laptop, tablet, mobile phone etc, then check out if the message is getting downloaded on those devices. If they arrive to the inbox of other apps, then clearly the problem is related to current profile. In that case, creating a new profile might help. Also, if a POP3 account is used, then make sure that you enable the 'leave a copy on the server' option so that all devices can successfully collect the mails.
Step 4: Check Email Arrival on Other computer/phones
If multiple rules are applied for sending or receiving emails, then possibility is that the mail is getting moved to a different folder or even deleted. Check out all the sub folders to ensure that the message that specific address is not passed to any other folder. For assurance, you can delete all the rules and then check if the problem persists.
Step 5: Check the Blocked Senders List
Make sure that you have not added the sender to the "Blocked Sender List". If the email address is added to the list, select it and click on 'Remove' button.