ASP. Net C# Web Not Secure Error & Subsequent Issues

mabr ali

I took an html template for an E-commerce Website. Which is made using bootstrap 4. I had two computers on which we were developing and debugging the Web. Using Visual Studio 2019 Community Edition. The Web debugs without any errors / issues. On these two systems. We tried the same project Using same VS on two other laptops with similar configurations. But on both of those laptops, all browsers; Chrome, Edge and Opera show "Web Not Secure Warnings". And gives "Invalid Postback Error" that can be seen in the screenshot.

Secondly, it wont let a secure connection with Gmail SMTP to send simple emails. Which also are getting sent using the other computers and the same browsers; Chrome, Edge and Opera.

Searched the web a lot. But there are multiple reasons and multiple solutions.

Trying them as well.

Any help would be appreciated. If anyone can help identify the core issue and its proper solution.

Thanks in Advance

5 Replies

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Satya Karki5y ago
Hi,

Just added a condition if(!IsPostBack) and it works fine :)
+1
Rijwan Ansari5y ago
I think you have some codes in your page_load events. If so, then you need to check Post bank as shown:
if (!Page.IsPostBack)
{ //do something }
This error is thrown when you click on your command and the Page_load is being ran again, in a normal life cycle will be Page_Load -> Click on Command -> Page_Load (again) -> Process ItemCommand Event
+2
Sachin Singh5y ago
Solution 1. I guess you are using javascript in your page that does a Postback and then updates some area of the webpage in success, if this is the case, then use AjaxUpdatePanel.

solution 2.Make sure your PageLoad even have this
if (!Page.IsPostBack)
{

//do something

}
solution 3. Most important:- As you said, you have copied the template from somewhere, there is a big chance that you have two form tag on the same page causing the error. You must have only one form tag either on the Master page or on child pages.
+2
Arnab Mukherjee5y ago
Try to enable SSL on local IIS and host your application locally and run it from IIS.

https://stackoverflow.com/questions/30240014/enabling-ssl-on-localhost-iis
+1
Pranam Bhat5y ago
Try these:

1) Try changing the port number.

2) Make sure CORS policy is not blocking.

3) Use "http://"

4) Clear cache and clear bowser history - all time.
+1