Google recently started rolling out its March Security Update for its Nexus and Pixel devices. The security patch was available at updated firmware page at Google Developers Site. Google has successfully pushed all its updates. Some of the users of Nexus 6 reported some issues with Android Pay after installing March Security Update Patch.
Nexus 6 security update seemed to interfere with the SafetyNet which is an essential component of Android OS. SafetyNet is an API which ensures the health and safety of Android devices. SafetyNet also examines the compatibility of software and hardware. The service also checks if the device is tempered or not and also assesses the trustworthiness of the apps.
Nexus 6 users started to report the problem even on devices which had previously passed SafetyNet. As we all know Google takes safety issues seriously and is very quick to respond. Google instantly removed the Nexus Factory Images from its Developers Site and started investigating the issue.
Google has re-uploaded the factory image and OTA file on their Developers Site and after examining it seems that it is the same file which was uploaded earlier. It seems that Google has temporarily disabled SafetyNet on the Nexus 6 to avoid issues with Android Pay. In the mean time Google is still investigating the real cause of these issues and will definitely provide a patch to resolve these issues soon.