Below are the different contact statuses and what they mean:
Active contacts are people who have not opted out and continue to receive messages from you.
An opted out contact is someone who has chosen to stop receiving messages from you. The most common way people opt out is by texting STOP to your number or clicking the unsubscribe link in their email. Once they are opted out, our system will no longer send them messages, and they will appear under your opt out contacts.
When using our optional double opt-in feature via a keyword or API, a contact will be sent an initial message that asks them to agree to be added to your list. If they don't agree, they remain in pending status.
Invalid contacts are categorized as numbers or email addresses that we can't send messages to.
home phone number
an expired number
a number that does not even exist
a shut off number
a bad email address
a full email box
an old email account.