Our best advice would be to connect the Top of Frame (ToF) output to the camera only (disconnect the wire from the DLS and your receiver) and measure the ToF pulse on an oscilloscope. There should be a 100ms pulse on the line each time the camera triggers. If you have a multimeter but not an oscilloscope, you may be able to see a brief change in the line voltage each time the trigger occurs, but it may be difficult to verify the levels. If you don't see a pulse, verify the settings on the camera configuration page, save the settings, and reboot the camera by holding the button.
Once the output from the standalone camera is verified, and you've verified the input voltage levels of the receiver are within the output of the camera's range (0-3V), then you should be able to connect the wire to your receiver. If there is a mismatch on the voltage levels, level translation may be required. For example, the camera outputs 0-3V, but the receiver may require 3.3V or 5V input levels.
Unfortunately we can only give general advice as to integrations, we aren't able to troubleshoot anything but the camera side of the integration. Once you have verified you can get pulses out of the camera, it may be necessary to work with the receiver vendor to troubleshoot the input side of the receiver.