I need guys help. I have a problem in my web site that was running on my local machine. Actually, months ago the page was working fine and has no error but now, it already has. The pop up message is "Line: 4723
Error: Sys.WebForms.PageRequestManagerServerErrorException: Object reference not set to an instance of an object." I dont know how to fix this. I tried so many ways that I've got from other site and forum but the error still pop up. Please explain to me what this error means, what is usually the cause and how will I fix this.
Thanks in advance.