On October 10th, we became aware of an issue with our iOS and Android apps reporting errors reaching our API, only affecting users on Verizon Wireless.
This issue does not affect receiving push notifications through Pushover, as those are related through Apple and Google servers, though downloading of notification image attachments and app icons is done through our API, which cannot be reached on Verizon. This would also affect reaching our website through the app or a web browser while using Verizon wireless for connectivity.
Upon gathering more reports, the issue appears to be DNS related, and Verizon is actively blocking the entire pushover.net domain for reasons unknown. Attempts to contact Verizon’s technical support and security team have been unhelpful.
We are encouraging Verizon customers to contact Verizon and report the problem so they are made aware of it.
Update 10/13: After receiving some DNS troubleshooting data from a helpful Pushover user on Verizon, it appears Verizon is using a 3rd party DNS filtering system which has erroneously flagged the pushover.net domain as having to due with malware (possibly due to the nature of how our API and callback mechanisms work). After contacting the company that is providing this DNS information, we are awaiting their delisting of our domain.
Update 10/13 17:00 CDT: We have released a new version of our Android app with a temporary workaround that tries a fallback domain if the pushover.net domain cannot be resolved. We are working on releasing a similar workaround for iOS.