Hello @mackh69 ,   Generally, SMS bounces are contacts that didn't receive your SMS message because the phone number was invalid. Essentially, it's the text version of a "the number you're trying to call is not connected." However, bounces can also occur if there's rate limits, throttling by the mobile carriers, etc.   For more info on SMS bounces and overall reporting, I'd recommend taking a look at this article. Considering the bounce rate you have, I would recommend calling our general support so our higher level technical team can do a deep-dive of the bounce codes we received, to determine if this is more caused by a technical element or because the numbers are truly invalid. ... View more