In addition, we need to know if your organization have a local Skype for Business server, or use Skype for Business online service? Will this issue occur to other users in the same organization? To protect your privacy, I will send you PM to collect it. General tab, click Collect Logs, then re-sign in Skype for Business, after the error message appear, please get the logs file(~/Library/Containers//Data/Library/Logs/). If issue persists, to better help you, could you please provide us the skype for business log for further investigation. Moreover, please try to reset Mac computer time zone and clock to see if it helps. Software? If yes, please temporarily close it and see the result. Greetings, I'm glad to follow up thread for you, since you can sign in your account in Skype for business for Windows, your account should be okay, may I confirm that if you have installed any Anti-virus
