When trying to renew an iOS certificate via Autoconfiguration tool, 'service is not available' message appears even if correct Apple ID & password are inserted.
Most probably, you have two-factor authentication enabled on your Apple account. Try to disable it and renew your certificate again using the Autoconfiguration tool.
While it may seem out of context, please visit https://itunesconnect.apple.com. Log in and accept the new Terms and Conditions, then try to renew your certificate once again in Pushwoosh Control Panel.
As an alternative you can always renew your certificate manually using our Guide.