The most common reason this is received is due to an email password change made in your email Account. Have you changed your email password recently? If so, you will need to update your password inside your CROSStrax SMTP settings. This can be done by following the below steps:
1) Go to "Settings" in the left-hand navigation bar, then click "E-Mail & SMTP" under integration
2) Enter your new password for your email account into the Password box, then click "Save"
If you are unsure of how to set up your email settings, please visit the article below:
https://support.crosstrax.co/a/solutions/articles/22000205749?lang=en