We have migrated our iOS app from the old sdk to the latest AmplitudeSwift sdk and the events no longer show up on the dashboard. After enabling the debug logging, we see that that flush events are failing. 

Debug: Skipping migrateInstanceOnlyStorages based on STORAGE_VERSION

Debug: Installing NetworkConnectivityCheckerPlugin, offline feature should be supported.

Log: Start flushing 2 events

Log: Start flushing 30 events

Log: Existing upload in progress, skipping...

Log: Existing upload in progress, skipping...

Log: Existing upload in progress, skipping...

Log: Existing upload in progress, skipping...

Log: Existing upload in progress, skipping...

Log: Existing upload in progress, skipping...

Log: Start flushing 30 events

We just see thousands of the same “Existing upload in progress, skipping” and “start flushing” over and over again. 

Any thoughts on why the flush is not successful?