How can I fix an error in the app.config file. I opened it and I saw <configuration> marked as error

[manny cash]

Hi people, blessings.

I got an error in the app.confg file. The error is marked in blue in this line <Configuration>, and I don't see anything else. Here is the code. I have never dealt with this kind of error.
Please, I would like your help. This error is beyond my basic knowledge.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8"/>
</startup>
</configuration>

 

[jmcilhinney]

If you build the project, what happens? If it fails, is there an error message in the Output or Error List window?

 

[jmcilhinney]

If you hover the mouse over that underlined code, is a message displayed?