No downlink messages with end device in ABP mode

Hi everyone!

I’m currently facing an issue with sending downlink messages from an end device that’s registered in ABP mode, class A. The problem arises when the device sends an uplink message to the server—the downlink message never seems to leave the downlink schedule. When the device is registered in OTAA mode, everything works fine.
I’ve attempted connecting the device to other network servers, and it functions well in those cases.
I’m wondering if there are any specific settings I could modify to resolve this issue, or if there might be a problem with the connection to the server itself.

Please do not double post - see explaination just posted to your earlier message…answer issue one and the same. This became an explicit need on TTN with transition from V2 to V3 (TTS(CE) in 2021.

Apologies for the double post. I wasn’t aware the problems were related. Thanks!