Problem witch device lock

I am facing an issue where a device successfully registers with the Chirpstack and sends its data.
I am also able to send data to the device, but after the first message is sent, the device gets locked. Subsequently, any data I try to send goes into a queue and remains there until the driver sends any packet. Once the driver sends a packet, the queue is released, and everything works correctly. However, if I restart the driver, the issue returns.
The end device is class C.
This problem occurs on Chirpstack v4.3, while it worked correctly on v3.
log message:
Mar 17 21:26:41 Chirpstack2 chirpstack[13360]: #033[2m2023-03-17T20:26:41.295797Z#033[0m #033[32m INFO#033[0m #033[2mchirpstack::storage::device#033[0m#033[2m:#033[0m Aquiring device lock #033[3mdev_eui#033[0m#033[2m=#033[0m70b3d5b020098199

Mar 17 21:26:41 Chirpstack2 chirpstack[13360]: #033[2m2023-03-17T20:26:41.295975Z#033[0m #033[31mERROR#033[0m #033[2mchirpstack::downlink::scheduler#033[0m#033[2m:#033[0m Schedule next queue-item for device failed #033[3merror#033[0m#033[2m=#033[0mGet device lock