We understand that there is currently no supported way to insert authentication in a Message Filter Extension. However, we are confused as to why the documentation suggests using shared web credentials in this context if they can't be applied due to sandbox restrictions. Doc reference: https://developer.apple.com/documentation/sms_and_call_reporting/sms_and_mms_message_filtering/creating_a_message_filter_app_extension Could you provide more clarification or update the documentation to reflect the current limitations? We asked the same thing in our post on the forum: https://developer.apple.com/forums/thread/758611 We also added a Bug Report FB14165508