I recently had trouble reading a DHT22 and DHT 11 on a photon using adafruit_dht library version 0.0.4. It seems to work on an argon, though intermittently fails about 5% of the time. The behavior was the same as for a previous topic I found in the troubleshooting section. The temperate was always zero and the humidity was 65535 or some version of that number. I had to downgrade to library version 0.0.2 to get it to work. I also was not able to get the pietech DHT library to work on the photon. I downgraded at least one version and it still did not work.
I wanted to put this in troubleshooting, but the option to add topic was grayed out. There is already a topic " Electron DHT22 Not Reading Temperature" that I wanted to add a solution to, but the topic was closed before a good answer seems to be provided.