Error: Error: Server did not return JSON and gave statusCode 403

[Softtik]

After generating the clients private key by using this command
./node_modules/bitpay-rest/bin/bitpay.js keygen
< enter a password, or hit enter for no password >
Generating keys...
Keys saved to: /Users/<your_username>/.bitpay
But when i enter this command ./node_modules/bitpay-rest/bin/bitpay.js pair
Hit enter
write no
Hit enter
write 1
Hit Enter
It gives me the error
Error: Error: Server did not return JSON and gave statusCode 403
at Request.handleResponse [as _callback] (/home/talha/Ammar/server-gotogods/node_modules/bitpay-rest/lib/rest-client.js:210:23)
at Request.self.callback (/home/jt/server/node_modules/request/request.js:185:22)
at Request.emit (events.js:182:13)
at Request. (/home/jt/server/node_modules/request/request.js:1157:10)
at Request.emit (events.js:182:13)
at IncomingMessage. (/home/jt/server/node_modules/request/request.js:1079:12)
at Object.onceWrapper (events.js:273:13)
at IncomingMessage.emit (events.js:187:15)
at endReadableNT (_stream_readable.js:1092:12)
at process._tickCallback (internal/process/next_tick.js:63:19)