I am facing below issue on custom web part. I developed this web part in vs2010 and deployed into SharePoint 2013 and framework version is 3.5.
The Web application at http://servename.domain.com:8899/xxx could not be found. Verify that you have typed the URL correctly. If the URL should be serving existing content, the system administrator may need to add a new request URL mapping to the intended application.
But this is working when use url like http://servename:8899/xxx.
I tried with by changing the build platform any CPU , x64 etc. but still i am facing same issue. Please provide any help to resolve this issue.