The error below appears in the logs:
javax.jcr.NamespaceException: Unknown namespace prefix: namespacename
Could not Build Package "Unknown namespace prefix: namespacename
Environment
AEM
Cause
This error usually shows up in environments where partial data migration was done using the crx2oak tool. The crx2oak tool doesn’t support migrating namespaces with the data.
5. At the bottom of the Namespaces window, click New.
6. Enter the URI and the Namespace mapping then click OK.
7. Enter the prefix of the Namespace mapping then click OK.