$ git remote set-url origin https://demodev@servername.com/home/demodev/public_html/waqtpar.git`
$ git push -u origin master`
fatal: unable to update url base from redirection: asked for: https://demodev@servername.com:/home/demodev/public_html/waqtpar.git/info/refs?service=git-receive-pack redirect: https://demodev@servername.com:/404.html`
Well, as the error says. You are getting a 404 error page which means website is not found. Git of course cannot handle this redirect in this case and so complains.
Your URL is simply wrong. Did you maybe want to use
ssh://demodev@servername.com/home/demodev/public_html/waqtpar.git
or
demodev@servername.com:/home/demodev/public_html/waqtpar.git
or