According to the link, "1020 - 1080 This email account has limited access to send emails based on suspicious activity. Blocks will expire based on the nature of the activity. If you’re a Spectrum customer, contact us to remove the block." If your IP has been mistakenly flagged for suspicious activity, only Spectrum can correct it. 'Suspicious' could mean anything from sending too many messages to sending messages regarded as spam by having too many links or remote images.