Strange issue that began occurring just recently (March 3, 2022)
Field Maps users are unable to sync changes made on iOS devices only from a downloaded map package hosted on Portal - Android devices continue to work normally. The error returned in the app is "Request Forbidden". This is not specific to any one map, or even any one portal in our organization - it happens only on all iOS devices (regardless of the iOS version) and regardless of the Field Maps version, and it is happening on different portals. The error only occurs if using a downloaded offline package and making edits - there is no error when downloading the package to the device and just viewing it, everything looks normal.
Field Maps does work correctly on all iOS devices on Portal only IF they are on VPN.
Field Maps does work correctly on all iOS devices on AGOL regardless of VPN.
So it appears the issue may be related to a recent policy change on our internal network, rather than anything to do with Field Maps or iOS. Digging into some of the logs a bit deeper, it appears there may be an error passing the token back to Server only when trying to sync edits made to an offline package.
Tracing the error backwards, it appears it may be happening before it reaches our internal DNS - as though something in the header may no longer being passed correctly, either in the Web Application Filter (WAF) , the DMZ Load Balancer or Apache Reverse Proxy.
Has anyone experienced similar issues? This one looks like it may be difficult to troubleshoot, so any ideas about how to proceed are appreciated.