Hi Anna,
To troubleshoot this issue, first please make sure the SIP and SMTP address of your Office 365 account should be the same, and the Office 365 account should be configured in your Outlook client.
SIP email address is what you use to log into Skype for Business client, and SMTP email address is the email address you use to configure your Office 365 account on Outlook.
To check SMTP and SIP, you can involve your admin to log the admin account to Exchange Admin Center. look for your account and then double click on the account. In the General Tab we would find the UPN Address and in the email address tab we would be find the SIP address for the user account. See the screenshot below:
If the SIP and SMTP email address has been the same, please refer to the methods below:
1. Update your Skype for Business client to the latest version based on this article: https://support.office.com/en-us/article/Install-Office-updates-2ab296f3-7f03-43a2-8e50-46de917611c5?ui=en-US&rs=en-US&ad=US . You can open any of your Office application to perform it such as Outlook.
2. Repair your Office application based on this article: https://support.office.com/en-US/Article/Repair-an-Office-application-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b . Same as above, you can open any of your application to perform it, for example, Outlook.
3. Try to clear the Skype for Business cache. To do this go to:
- Navigate to %localappdata%\Microsoft\Office\16.0\Lync folder.
- Delete your sip profile folder.
- Open Tracing folder, delete all the contents inside, but not the Tracing folder itself.
- restart the computer to refresh.
4. Do others in your organization also encounter this issue?
5. Do you use Office 365 Cloud-based account or your organization have some On-Premise server such as Exchange Server and Skype for Business server?
6. The version of Skype for Business client. You can check it by opening the Skype for Business client> Settings>Help>About Skype for Business. See the screenshot below:
Thanks,
Amanda
