Couldn't send app's data error during app migration
Platform notice: Server and Data Center only. This article only applies to Atlassian products on the Server and Data Center platforms.
Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Summary
Learn what causes and how to solve this error message when migrating apps with the Jira Cloud Migration Assistant (JCMA).
Overview
When migrating apps with the Jira Cloud Migration Assistant (JCMA), apps can get stuck at 0% progress without further indication.
Looking at the application log file atlassian-jira.log, you can see one of the below errors:
ERROR ServiceRunner [c.s.j.attachcategory.migration.SmartAttachmentsCloudMigrationListener] Couldn't send app's data.
java.lang.NullPointerException
at com.atlassian.jira.migration.amsclient.DefaultAppMigrationServiceClient.uploadToS3(DefaultAppMigrationServiceClient.kt:278)
at com.atlassian.migration.app.MultipartUploadStream.getSignedUrlAndUpload(MultipartUploadStream.kt:64)
at com.atlassian.migration.app.MultipartUploadStream.close(MultipartUploadStream.kt:44) ERROR ServiceRunner [c.s.j.attachcategory.migration.SmartAttachmentsCloudMigrationListener] Couldn't get mappings (transferId=<transfer_id>, namespace=jira:fileAttachment).
com.atlassian.jira.migration.httpclient.exceptions.HttpCommunicationException: An error occurred when requesting against resource https://api.atlassian.com/app/migration/mapping/<mapping_id>/find?namespace=jira:fileAttachment: Timeout waiting for connection from pool
at com.atlassian.jira.migration.httpclient.exceptions.ExceptionsKt.communicationError(Exceptions.kt:13)
at com.atlassian.jira.migration.httpclient.AbstractPluginHttpClient.execute(AbstractPluginHttpClient.kt:72)
at com.atlassian.jira.migration.httpclient.AbstractPluginHttpClient.execute(AbstractPluginHttpClient.kt:56)ERROR ServiceRunner [c.s.j.attachcategory.migration.SmartAttachmentsCloudMigrationListener] Failed onStartAppMigration
com.stiltsoft.jira.attachcategory.migration.CloudMigrationFailedException: Couldn't get mappings (transferId=<transfer_id>, namespace=jira:fileAttachment).
at com.stiltsoft.jira.attachcategory.migration.SmartAttachmentsCloudMigrationListener.getMappingByIdWithRetry(SmartAttachmentsCloudMigrationListener.java:220)
at com.stiltsoft.jira.attachcategory.migration.SmartAttachmentsCloudMigrationListener.getPreparedMigrationAttachmentToCategory(SmartAttachmentsCloudMigrationListener.java:130)
at com.stiltsoft.jira.attachcategory.migration.SmartAttachmentsCloudMigrationListener.lambda$getAndSendAttachmentMaps$3(SmartAttachmentsCloudMigrationListener.java:111)
All the above errors are an indication that the Jira On-Premise instance is failing to communicate with the App Migrations service.
This can be caused by network hiccups or middleboxes like Firewalls and VPNs blocking the connection.
Solution
Make sure all hostnames for the JCMA plugin host communication are allowed within your network infrastructure.