Collector XYZ is not initialized in DAAS service. Response Code: [204]

Hello,

I'm trying to run IG 4.2 behind a cloudflare tunnel but IG doesn't seem to like that.

In the Identity Sources I've added "Identity Manager Identity Collector - Template Version 4.2.0" and clicking on "Test connection" returns "Connection successful."

But when I start a collection, it fails after a while with the following message:

Collector IDMDEV is not initialized in DAAS service. Response Code: [204]
The catalina out looks like this:
[INFO] 2024-05-08 09:40:42.292 [com.netiq.iac.server.dtp.DataProcessingTask] [IG-SERVER] Successfully invoked data collection execution service for collection id = 669, collector id = 5
[INFO] 2024-05-08 09:40:43.602 [com.netiq.daas.daaservice.util.Service] [DAAS] Service 'IDMIdentityTemplate-4-5-8cadcda98f8e4bb1ae0798be4b5172ed' connector information: JAR: 'opt/netiq/idm/apps/tomcat/webapps/daas/WEB-INF/lib/daas-ldapex-native-4.1.12.0000.jar', VERSION: '4.1.12.0000'
[SEVERE] 2024-05-08 09:40:46.469 [com.netiq.iac.persistence.dcs.dce.thread.DataCollectionServiceThread] [IG-DTP] Collector IDMDEV is not initialized in DAAS service. Response Code: [204]
Does IG have any special requirements when running behind a "reverse proxy" ?
Could it be that the proxy changes the response code to 204 and IG expects something else?
Thanks.