Calling LoadLibraryEx on ISAPI filter Failed

Brand new CF, right? No CF lockdown applied? No change to IIS default settings? Just vanilla new site? Just want to get us on the same page.

And can you confirm you ran the CF web server config tool after installing CF? Or did you perhaps manually add in the IIS settings pointing to that DLL above? If you ran the tool, did you tell it to configure "all sites" or a given site? Did you use the "run as admin" feature when you ran that tool?

When I've seen this error, it was because of either of two issues:

1) Someone let CF implement a 64-bit connector (the default), but the IIS App pool was set to be 32-bit. See the site's app pool, and its "adv settings", and the "enable 32-bit" option and set it to false. Or if it is false, did you perhaps tell CF's web connector tool to create a 32-bit connector? It's an option, but not on by default.

If this is the issue, check all app pools that use CF--and consider changing the "app pool defaults", done via a link on the top right of the IIS UI when you are looking at app pools.

2) Or, someone changed permissions in either IIS (for the site and/or app pool) or for the CF folder (where that DLL lives, and which IIS points to and loads into the app pool).  Changing permissions to allow the app pool user to access that folder has solved it.

A challenge is how to add the app pool user. The default identify for an app pool is called the "app pool identity". If you did not change it, the default user is of a form "IIS APPPOOL\AppPoolName", where you must type that name (you won't find it in the Windows security browse feature for existing users). Or you may find you could use the IIS_IUSRS group. For more on those, see resources like https://support.microsoft.com/en-us/help/4466942/understanding-identities-in-iis.

And let us know how it goes.