java - Invalid:error connecting to backend after clicking on API publisher test button -

i configured wso2 api manager product on unix environment.i able login carbon,publisher , store url using dns name of server.by using below url able access carbon, publisher page::

https://abc.xx:9445/carbon

for testing purpose deployed sample application in publisher. url try hit publisher api:: https://abc.xx:9445/am/sample/pizzashack/v1/api

but after clicking on test button(i.e. production endpoint) using dns name of server gives me invalid:error connecting backend.checked log shows connection timeout **https://abc.xx:9445/am/sample/pizzashack/v1/api**url.

if use ip instead of dns name gives me bad certificate error in log.

any appreciated!!