Web.config Custom Errors mode Conflict

Question

I have a great and important problem with Web.Config, I need to see the Error of my page and resolve it in asp.net web form and web config, but when Error Occurred, I see an

Answer 1

First, you can set CustomErrors mode from "RemoteOnly" to "off"

Second, You can check the global.asax.maybe you create Response.Redirect as same as defaultRedirect in customError. you can check more detail in here ASP.NET customErrors with mode=remoteOnly and global.asax handling exceptions

and the last,maybe you create two system.web in your webconfig. You should only have one in your config file.please check again your webconfig. and dont forget