Skype for Business error KB2566790 when logging in using organization office 365 accounts.

Question

I was asked to setup skype for business by my client, after installation whenever i tried to login using the organization office 365 accounts it says error KB2566790 and asking me to check the dns server, upon checking it shows that the dns record that the error KB2566790 requires the CNAME and SRV are both present and correct but is not responding when using dns checker and nslookup, i read somewhere here that those records are dead so how can I fix the error KB2566790 if they don't respond anymore.

Answer 1

Hi @kenmarc jorizen calantog

It sounds like you're experiencing some DNS issues with your Skype for Business setup. The error KB2566790 indicates that there may be problems with the DNS records required for Skype for Business. Although you mentioned that the CNAME and SRV records are present and appear to be correct, they aren’t responding properly. Here’s what you can try to resolve this issue:

1. Double-check DNS records: Ensure the DNS records are absolutely correct and have propagated fully across all DNS servers. Here are the key DNS records you should have:

• CNAME Records: - lyncdiscover.yourdomain.com pointing to webdir.online.lync.com - sip.yourdomain.com pointing to sipdir.online.lync.com
• SRV Records: - _sip._tls.yourdomain.com pointing to sipdir.online.lync.com with port 443 - _sipfederationtls._tcp.yourdomain.com pointing to sipfed.online.lync.com with port 5061

2. DNS Propagation: DNS changes can sometimes take up to 48 hours to propagate fully. Ensure you have waited enough time for the changes to take effect.
3. Clear DNS Cache: On the client machine where you are trying to log in, clear the DNS cache. You can do this by running the following command in Command Prompt:

ipconfig /flushdns

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