IIS Express Visual Studio - Cannot debug localhost

Question

Been trying to resolve this issue for a few days now. I've done a ton of searching and tried several solutions - nothing has helped thus far.

I have a Visual Studio 2017 project. It has been running and debugging fine for years now. Suddenly, the other day I can no longer debug the application. Regardless of what browser I select (IE, Edge, Chrome, Firefox, etc) - the same error message is generated:

INET_E_RESOURCE_NOT_FOUND

Also, it takes forever for VS to open the browser to show this message. Additionally, if I start without debugging (ctrl + F5), the site works and loads as expected.

Things I've tried thus far:

• Deleting everything from the IIS Express folder in My Documents
• Re-installing IIS Express
• Repairing IIS
• Changing the port number in the project
• Various IIS Express reset commands
• Resetting IE settings
• Clearing caches

There are probably a few others too, but at this point I feel I've exhausted all my options.

Anyone else encounter this and if so how did you fix it?

Answer 1

It turns out the issue was a corruption in IIS (and likely its certificates). I was able to fix it by following the instructions found here:

Visual Studio 2017 Removing SSL/TLS Connections Problems with IIS Express

One quick note: for projects that already have SSL Enabled set to True, simply toggle the flag and Visual Studio will assign a new SSL port number.

More Info: I attempted to debug an application I'd run several times after performing the steps listed in the linked article from PluralSight (tried that several times to ensure I wasn't missing anything). The symptom re-appeared- any browser would indicate the page didn't exist. I noticed that IIS Express was not running - didn't open at all; or at least not noticeably. I unchecked the "Enable Edit and Continue" option as discussed in this post: IIS Express Immediately Shutting Down Running Site after Stopping Web Application. Though the symptoms didn't match exactly, it was a simple-enough option to try. Sure enough, the site was operational once again. I'm running Visual Studio 2017 Version 15.6.4. Not sure if this is related to Visual Studio or IIS Express, but unchecking the "Enable Edit and Continue" seemed to resolve the latest hang up.

Answer 2

I had to set my start page to Default.aspx again. I don't know how it got unset or why it would result in that INET_E_RESOURCE_NOT_FOUND error.