Last Updated on December 2, 2020
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Skype for Business is part of the Office 365 package. Skype for Business provides affordable collaboration tools for your business. However, if you try to sign in to Skype for Business, it may happen that the address you entered is not a valid error.
Several users reported similar issues in the Microsoft community when they signed into Skype for Business on Windows.
If you also encounter this error, here are a few troubleshooting tips you can use to resolve your login problems with Skype for Business.
Check DNS records for a domain
- Incorrect domain DNS records may mean that the address you entered is not a valid error, because Skype for business cannot contact the server due to the absence or incorrect DNS records.
- To solve this problem, make sure that you have added the correct DNS records to your domain/hosting provider’s website.
Adding DNS records for your domain
- Microsoft provides detailed instructions on how to add or create DNS records with any DNS hosting provider for Office 365.
- You can find more information about the same access to creating DNS records for Office 365 here.
- The following guide looks at adding TCT or MX records along with CNAME records.
The problem may be caused by an error when saving data or installing the application. This leads to data corruption and operational problems.
It turns out that removing the Lync cache can help solve the problem. Cached data can often be corrupted and even after deleting an application, the data remains. This can cause problems even if the application is reinstalled. Version 15.0 may vary depending on the Office version you have installed. How to uninstall a Lync cache
- First press the Windows + R key.
- Then enter the following in the “Run” field
- % User Profile% \ AppData \ Local \ Microsoft \ Office \ 15.0 \ Lync \ [email protected]
- Delete the folder of the local user.
- Now open the “Run” window again and type regedit.exe.
- Then browse to the following directory
- HKEY_CURRENT_USER \ Software \ Microsoft \ Office \ 15.0 \ Lync \ [email protected]
- Delete the registry key and save the changes.
- Finally, also delete your Skype accounts. On the Skype for Business login page, click Clear Credentials.
- This step removes all passwords, certificates and connection settings saved for your Lync user account.
- Log in and see if the problem is resolved.
Try to remove / update the user SIP certificate.
- Open the certificate manager by selecting Start> Run and typing certmgr.msc.
- Expand Personal> Certificates.
- Sort by column Who issued and find the certificate issued by the communication server.
- Delete the certificate.
Delete user URI
- Open Regedit, browse the following path and delete the folder: HKEY_CURRENT_USER \ Software \ Microsoft \ Shared \ UcClient.
- Browse to HKEY_CURRENT_USER \ Software \ Microsoft \ Office. Then open 15.0 or 16.0 depending on your Office version.
- Find the Lync key and open it.
- Remove data from the ServerSipUri and ServerUsername strings.
Upgrade Windows to the latest version
If the above steps do not work, you may have to wait for a fix from Microsoft. Check if there are any pending Windows updates. For many users this problem has been solved with Windows KB3114502 or KB 3114687 for Lync. If the problem persists, check for updates and install them, if available.
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CCNA, Web Developer, PC Troubleshooter
I am a computer enthusiast and a practicing IT Professional. I have years of experience behind me in computer programming, hardware troubleshooting and repair. I specialise in Web Development and Database Design. I also have a CCNA certification for Network Design and Troubleshooting.