.Net WPF Application Error Fixing

my application is web based. it build on .net wpf framework. currently my admin panel is not opening and same time my clients also cannot login into their tools. same time my website also stopped opening which is build on php and its a issue from server side. we have been facing this issue for 15 days. This project would be long term project as if you fix it i would like to give my whole project to that person Permanently.