Dear Support,

I've a Lync Web App problem:

in external network, i create a web meeting via Skype for business client on PC1, i share the meeting URL (http//meet.sipdomain.com/Kenny.F/SD14MH0H) to other external PC, they cannot access it and got "no responding" error, but when i use meet link with"?sl=1" to force access on the PC1, it works, would you please advise how to do the trouble shooting?

many thanks.

You can follow these troubleshooting steps to solve lync web app problem

https://support.office.com/en-nz/article/Trouble-installing-the-plug-in-3dba99b4-0f57-4ed7-9d70-682188c53404