I am having problems with Downlink Messages

I am operating in the US with the 915 bands. I am receiving uplink messages very well. When I send a downlink message, the TTIC gateway sends an S7BW500 message on random downlink channels. Downlink messages are not received by the end device.

I am using a Seeed Studio Lora-E5 as the end device. The RXWIN2 channel is 923.3 and DR8.
I am using mqtt to send the message to the device.

Is there a setting on the end device, mqtt message or in the specification of the device in the things stack to fix the downlink problem?