After Pyramid 2018 installation, when using the IIS option, if you cannot access the Pyramid 2018 from a browser using the IIS bindings you chose, please check, in the control panel, if the following IIS modules have been installed :

If either or both "IIS URL Rewrite Module 2" and "Microsoft Application Request Routing 3.0" have not been installed, please download and install them using the links below:
Note, that before installing them, you'll need to close IIS first.

• Microsoft Application Request Routing 3.0https://www.iis.net/downloads/microsoft/application-request-routing
• IIS URL Rewrite Module 2
  https://www.microsoft.com/en-us/download/details.aspx?id=47337

Once the above two IIS add-on's have been downloaded, run the installer and follow the on-screen prompts.

Once Pyramid 2018 installed, activate the proxy that will be installed as shown below:
Open IIS >Double click on the server name(1)>Double Click on "Application Request Routing Cache"(2)
 

Tick the box "Enable proxy"(3)>Click on Apply(4)
 
Once the above steps have been done, please do an IISRESET and then try to access Pyramid 2018 again.