How you collected your contact’s information and how they granted permission to be contactedįor additional best practices to ensure message delivery, please see this guide here.Serb Djokovic wrote 'Kosovo is the heart of Serbia.

Brief summary of your business and your usage of OpenPhone.

If you believe your messages are compliant with our terms of service and that you’ve only contacted users that have opted to be contacted, then please submit a request here with the following:

If blocked by the receiving carrier’s end, this means your message was flagged as spam by the receiving carrier. If blocked by OpenPhone’s end, this means that your messaging violated our terms of service. If a message you sent returns the above error message, then your message failed to deliver because your message was filtered, or blocked, by either OpenPhone or the receiving carrier. Your message content was flagged as going against carrier guidelines Please include 3 or more specific instances of this issue in your message. If you’re consistently experiencing the unknown error message, please reach out to our support team to further troubleshoot. To check on this, please go to our status page at While uncommon, it’s possible that a message fails to send for this reason due to a temporary outage with OpenPhone. It’s also possible that the message failed to send from something on your end, including a poor internet connection. If a message you sent returns the “unknown error” message, then this means that the message failed to deliver and the error notification that we received from the receiving carrier did not specify the exact issue. If you’re consistently experiencing this issue,please reach out to our support team to further troubleshoot. Else, the destination is otherwise unreachable. The most likely reasons include that the destination is a landline. If a message you sent returns the above error message, then your message failed to deliver because the recipient is unable to receive this message. Potential reasons could include trying to reach a landline or, in the case of short codes, an unreachable carrier. The destination number is unable to receive this message. If you’re able to rule out the above issues, please reach out to our support team to further troubleshoot.

The receiving carrier filtered out the message as spam.The user cannot receive SMS due to limitations of their mobile plan.The user does not accept SMS from unknown senders.If a message you sent returns the above error message, then your message failed to deliver because the destination is blocked from receiving this message. The destination number you are trying to reach is blocked from receiving this message. Please include 3 or more specific instances of this issue in your email. If you’re experiencing repeated instances of this issue, please reach out to our support team at to further troubleshoot. While unlikely, it’s also possible that the receiving carrier sent us this error message after filtering out the message. This might mean that the contact you’re trying to message is outside of cellular service or their mobile device is turned off and unavailable to receive messages. If a message you sent returns the above error message, then your message failed to deliver due to an unavailable or unreachable destination. The destination handset you are trying to reach is switched off or otherwise unavailable. If you believe that the number is an active number and you’re receiving the above error message, please email our support team at with a brief description of your issue to further troubleshoot. It’s possible that this number is no longer in service or has been temporarily deactivated. If a message you sent returns the above error message, then your message failed to deliver due to an unknown or inactive destination.

The destination number you are trying to reach is unknown and may no longer exist On the web or desktop app, you can highlight over the undelivered notification and see the specific reason why your message didn’t go through. If you receive the undelivered notification on your message, this indicates that OpenPhone has received a delivery receipt indicating that the message did not deliver. If you’re having issues with messages failing to deliver but you did not receive an undelivered notification, please see this article. In this guide, we’ll cover any outbound messages that register an undelivered error notification. Are your outbound messages showing as undelivered? There’s usually a simple explanation! We put together this guide to help you troubleshoot and resolve any issues with your messages not delivering properly.

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