Cannot read configuration file due to insufficient permission, Error 500.19 (0x80070005)

So i'm having this error for 2 days looking for an solution but nothing works...

What it says is this:

https://gyazo.com/4cd854b40ea311d8c9f81f401ae901bf

I've tried these methods but they don't work:

1. Click Properties.
2. Click the Security tab, and then click Edit.
3. Click Add.
4. In the Enter the object names to select box, type computername\IIS_IUSRS, click Check Names, and then click OK.
5. Note Computername is a placeholder for the computer name. Click to select the Read check box, and then click OK. In the Properties dialog box for the folder, click OK.

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The web.config file is an XML file would that be a problem?

I've tried many other forums and websites and even contacted microsoft but nothing seems to fix it.

As of the IIS_USRS i cant seem to find it. But i read that it's the same as an admin account.

Thanks in advance.