You should first check to see if there are any mistakes in your email address. Look to see if you have a typo or other type of error that would make it invalid. Additionally, verify if the domain extension is correct. If that still doesn’t resolve the issue, contact your email provider’s customer service or contact the website you are trying to access. It might be helpful to tell them the email address that is not working and any other details that might be useful.

1. Check for typos or other errors in your email address.
2. Verify that the domain extension is correct.
3. Contact the email provider or the website you are trying to access.
4. Provide your email address along with any other details.