Microcoap does not respond except in Copper

[mishoboss]

I try to make Microcoap works on esp8266. And it works good! But only when tested with Copper in Firefox. I don't get request response when I try to access it with node-coap (https://github.com/mcollina/node-coap/). The node-coap response event doesn't fire.

I found a similar question with (probably) the same issue here: https://stackoverflow.com/questions/31369908/can-not-connect-to-coap-resource-on-arduino

Node-coap works with "coap://coap.me:5683/", so I guess the issue should be in Microcoap, or maybe some protocol implementation difference? Any ideas are welcome.

[jdkanani]

Related to #8

Removing memset line will do the trick. Check commit mbialon@3cf97f9