If you've already checked your sending windows, made sure that the campaign is active(not paused), your seat is active, and haven't reached your daily limit, here's what we can try to do.
- Go to the mailbox settings.
- Disconnect the mailbox.
- Reconnect the mailbox.
- If you're getting an error such "attempting to reconnect" and unable to disconnect the mailbox, please contact support.
Hope that helps!