Problem
The "TopicDisallowed" error occurs when sending a push notification to a reachable user in iOS.
Explanation
This error happens when the Bundle Identifier in the MoEngage push settings (associated with the AuthKey .p8 file) does not match the app's Bundle Identifier where the push notification is being tested.
Example
If the app’s Bundle Identifier is com.xyz.moengage, but the Bundle Identifier linked with the AuthKey is com.abc.moengage, this error will occur.
Solution
To resolve the "TopicDisallowed" error, the development team must address the abovementioned issue.