ProblemWhen accessing the meet url from outside the corporate network you get the error Server error 500 – Target Principal Name is incorrect

When you tickle the TMG rule the traffic is redirected to the Lync FE, however the requested URL [eg. needs to be in the internal FE cert…
Simply update the cert. So the internal cert will need, when youo run through the cert wizard on the FE it will auto populate the cert accordingly