You have undelivered emails waiting for you
There is a phishing campaign targeting Microsoft Outlook users stating they have undelivered emails waiting for delivery to their inboxes. The phishing email asks the user to decide on each waiting email individually and prompts the user to enter in their credentials to unlock the waiting email. By doing so, the user just submitted their username and password to the hacker.
Phishing emails have become a lot less successful over the years as education and awareness has increased and improved, but all it takes is one phishing email to compromise an account or a business network. Regular awareness and training is necessary to minimize the chances a small business employee submitting their usernames and passwords to a hacker. Trust, but verify.