Hi Guys,

I have lync server 2010 on-prem, and i can access my lync from external network.
Now I want lync server 2010 can be communicate with lync online.
i've add External user access provider at lync on-prem and add domain at external organization lync online.

but still can't communicate.

please advice.

thanks,
Surya

Hi Surya,

Is it same domain name or different domain name for onperm and Lync Online ?

it is different domain.

Thanks,

HI

You need to have a SRV record created 

SRV

_sipfederationtls.mydomain.com

sip.mydomain.com