Inbound Calling Incident
Incident Report for CallHarbor
CallHarbor has continued to observe normal network behavior and inbound call performance today. At this time the upstream carrier is continuing to report stability and is monitoring. CallHarbor will reopen a new incident provided issues reoccur at the upstream carrier level.
Posted Sep 30, 2021 - 14:35 EDT
CallHarbor has been observing normal inbound call performance. At around 7:30PM ET it appears that Cloudflare may have suffered an outage or attack which resulted in some call failures at the upstream provider as well as multiple websites going offline globally this was since resolved. Outbound calling continues to be unaffected.
Posted Sep 29, 2021 - 21:54 EDT
We are currently seeing issues limited to primarily Verizon Wireless / Verizon subscribers. We will continue to provide information as we receive it.
Posted Sep 29, 2021 - 10:08 EDT
CallHarbor continues to see intermittent issues with inbound calls due to the upstream carrier. We will continue to provide more information as we receive it.
Posted Sep 29, 2021 - 09:51 EDT
At this time we are continuing to observe normal behavior. We will be leaving this incident open and provide updates throughout the day if any changes occur.

The upstream carrier has marked this incident as resolved.
Posted Sep 29, 2021 - 07:46 EDT
CallHarbor will continue to leave this incident open while we monitor the situation. At this time the mass majority of calls are functioning as expected. Incoming calls may in some cases experience one-way audio, or Verizon numbers may have issues calling in intermittently, however this the minority. Any issues experienced with inbound calls are still related to this incident impacting our upstream provider. We will continue to provide updates as we receive them.
Posted Sep 28, 2021 - 17:32 EDT
We are continuing to monitor for any further issues.
Posted Sep 28, 2021 - 15:47 EDT
CallHarbor currently has no updates from the upstream carrier, however calls appear to be processing as normal at this time.
Posted Sep 28, 2021 - 14:15 EDT
CallHarbor continues to see intermittent issues with inbound calls, however it does not appear to be consistent nor have the severity as yesterday. We will continue to monitor and provide updates where possible.
Posted Sep 28, 2021 - 12:14 EDT
CallHarbor is reopening this incident as we are beginning to see increased latency, and post dial delay on inbound calls. We are currently not seeing call failures, however we are continuing to monitor the situation. The upstream carrier has not released any updated information today at this current time.


Our primary upstream carrier for inbound calling and inbound and outbound messaging on the PSTN is currently experiencing an attack on its network. Many if not most of the United States largest VoIP and cellular providers utilize this upstream carrier to provide connections for voice inbound and outbound.

Due to the way that telephone numbers work, we cannot set up a failover in the event that our main upstream carrier experiences an attack. We selected our upstream carrier based on multiple decades of great service and uptime, this is also why many of the other VoIP and cellular providers as well as largest organizations on the planet have chosen them.

Outbound calling can support failover and all of CallHarbor's outbound calling traffic has been migrated away from this upstream carrier who is experiencing an attack. As the attack is ongoing there may be periods of poor audio quality inbound, or inbound call failures.

If you are experiencing an issue inbound or outbound do not hesitate to reach out to CallHarbor we are here to help, we are still looking through all poor audio or call issues to determine cause and resolve where possible. In the event that the issue is caused by this upstream carrier attack we will inform you.

We are working with our other major carrier partnerships to build a plan in the event that this attack on this major carrier appears to extend in time. This would take some time to implement (due to porting restraints nationally) however we are prepared to protect you and your business.

CallHarbor is currently having no issues with its own network, or extension to extension calling; Furthermore some CallHarbor customers do not rely on this upstream carrier for service and will be unaffected by this attack.

If you are having trouble reaching CallHarbor support through our main line you may dial our alternative support line: 313-644-7500

We will continue to provide updates at in order to be as transparent as possible regarding the current issue affecting VoIP providers nationally.

NOTICE: In the event of an emergency where 911 needs to be reached please utilize cellular networks where possible.
Posted Sep 28, 2021 - 10:05 EDT
This incident affected: Calling (Inbound).