Error occured while generating an OAI response: Root element not set null

[John Milano]

Hi,

I am using DSpace 4.3 and trying to harvest metadata using DSpace Harvester via OAI-PMH from a remote repository.

The harvesting has been working before, but becaue the source repository changed to https it stopped.

After correcting the source link in the harvesting admin panel, I get the following error in the logs:

ERROR org.dspace.harvest.OAIHarvester @ Error occured while generating an OAI response: Root element not set null

and no new records are harvested, although the logs show that new records are available:

INFO  org.dspace.harvest.OAIHarvester @ Found 13 records to process

...

INFO  org.dspace.harvest.OAIHarvester @ Item document/173902(174452) has been ingested. The whole process took: 16 ms.

...

INFO  org.dspace.discovery.SolrServiceImpl @ Wrote Item: document/173902 to Index

...

Any idea?

Regards,

John