If you haven't received an email with your login code then the first thing to do would be to check your spam/junk folder.
If the email is not there, then the next step would be to add Countingup to your safe senders/whitelist. This will ensure that the email makes it into your inbox and is not blocked or added to a spam folder. Here's how you add contacts to a safe senders list for Outlook, Gmail and Apple Mail.
Once you have added Countingup to your safe senders list, restart the process and request a new code.
If this still does not resolve your issue, please consider using an alternative email address or waiting 24 hours and trying again.