Sometimes it may happened that you are trying to configure a website (Asp.net) on a machine and you will find the error
“HTTP Error 500.19 – internal server error”
“The requested page cannot be accessed because the related configuration data for the page is invalid”
So here are some basic tips which you should follow and hope everything will work fine after this.
1) Re check the IIS installation whether the IIS installed properly or not for this go to control panel and click on windows Features and check whether IIS application development features installed or not as shown in below fig.
If not installed the install it and re check the website.
2) Once you have checked everything is installed file but still the site is not working then try to assign proper application pool for application (Default Application pool or default 4.0 application pool etc.) and check it.
3) If still the site is not working then try to give proper permission to website folder. Give proper permission for IIS_USER or everyone.
This things helped me, I hope this will resolve your issue.
Thanks & Best Regards,