HTTP 404. The resource you are looking for could have been removed

Environment:

Skype for Business (SFB) Server 2015 Standard Edition

Issue:

When sending an internal/external meeting invitation , the end user clicks on the meeting link and is given the error:

The resource cannot be found.

Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.

Requested URL: /lwa/WebPages/LwaClient.aspx

I opened IIS and found that the LWA virtual directory was missing.

The next step was to reinstall the LWA, when I opened up the Skype for Business Management shell and browsed to C:\Program Files\Skype for Business Server 2015\Deployment and re-ran the bootstrapper.exe it didn’t fix the problem. So here is what I did to fix the issue:

Mounted the Skype for Business Server 2015 ISO file
Browsed to Drive Letter:\Setup\Amd64\Setup
Double Click EnterpriseWebApp.exe
There wasn’t a repair or change option only a Remove, so I clicked remove.
Once the software was removed I re-ran the bootstrapper and then checked IIS and the LWA virtual directory was there and meeting invitations began to work.