sitecore - Coveo Search REST Endpoint () 503 -

i facing issue sitecore coveo installation on dignostic page

the remote server returned error: (503) server unavailable. (hide details) system.net.webexception: remote server returned error: (503) server unavailable.    @ system.net.httpwebrequest.getresponse()    @ coveo.searchprovider.applications.stateverifier.<>c__displayclassd.<getrestendpointstate>b__c()    @ coveo.searchprovider.applications.baseverifier.verifycomponent(func`1 p_verifymethod, string p_componentname) 

although have found solutions related on forums not 1 reflect same. https://answers.coveo.com/questions/1974/rest-endpoint-the-remote-server-returned-an-error-503-server-unavailable same goes below error not reflecting or fixed using provided solution. https://developers.coveo.com/pages/releaseview.action?pageid=14058186

thanks

since "server unavailable" exception "coveo search rest endpoint" component, should ensure that:

• the "coveo search api" software installed either on coveo enterprise search server or sitecore server depending on infrastructure.
• the "coveo search api" windows service started on machine installed on.
• the "coveo search api" logs doesn't contain recent errors may prevent run correctly.
• the "coveo search api" listening port (default 8080) not used other software on machine "coveo search api" installed on.
• the "coveo search api" listening port not blocked firewall.
• the server on sitecore installed not block requests "coveo search api" listening port.
• you can access "coveo search api" url (default http://servername:8080/rest/search) browser on server on installed.
• you can access "coveo search api" url browser on server on sitecore installed.
• you can access "coveo search api" url browser on computer.
• you can access coveo sitecore rest endpoint proxy url (default http://sitecoreinstancehost/coveo/rest) browser on server on sitecore installed. (/coveo/rest must in lowercase)
• you can access coveo sitecore rest endpoint proxy url browser on computer.

let me know if helps.

jeff