Microsoft Skype for Business on Windows displays a red exclamation mark in the toolbar that, when moused over, states:

There are Exchange connectivity issues. Your conversation history cannot be retrieved.

In the bottom right corner of the main Skype for Business window, an icon may appear indicating server connection problems.

In addition to the error referenced above, you may experience the following symptoms:

• Your conversation history is not being saved in the "Conversation History" in your TechMail mailbox as usual.
• You cannot save Skype for Business conversations to an email message.
• You cannot send mail to a Skype for Business contact.
• You cannot search personal Outlook contacts from Skype for Business.
• When your account is viewed by an IT support professional using the Active Directory Users and Computers MMC snap-in, the E-mail field may not be populated, and your account may not have an Exchange license.

You may be either not correctly connected to your TechMail account or may have been locked out of your TTU domain account.

You also may have incorrect credentials stored in Windows Credential Manager.

1) Make sure Outlook is set up correctly and is connected to your TechMail account.

2) Check Windows Credential Manager for saved credentials that might be in use but are not current/correct. You can remove them, and Outlook or Skype for Business will prompt you for them if needed.

Outcome

Skype for Business will successfully connect to your TechMail account again.