If you have recently changed your password for an email address or there is an error with your email provider, you will probably see a note from our system asking you to reauthenticate your login credentials soon after. Until you reauthenticate, your account will stop syncing and you will not be able to send emails.
If you're using Polymail Web our macOS:
You will see a red banner at the top of the app's main page:
You will also see a note in your Accounts page in Settings letting you know which email address needs to be reauthenticated. The email address will be red and you'll see a button next to it to start the reauthentication process:
You can click either this blue "Reauthenticate" button in the Accounts tab of your Settings or the "Click here" in the red banner at the top of the main page. You will be taken to your email provider's interface in a new tab in your internet browser where you can either choose your address or re-enter your password manually.
If you're using our iOS app:
You will see a banner at the very top of the screen letting you know you need to re-authenticate an email address:
Clicking on the prompt at the top will open a new tab in Safari and allow you to re-enter your credentials there.
Once your account has been reauthenticated, Polymail will automatically resume syncing your mail and you can send email.