What are the hours and when should I call? Microsoft - Product Support operates the call center for this 888-212-3545 MSN phone number 24 hours, 7 days. https://himss.zendesk.com/hc/en-us/community/posts/36979566495251-How-to-Sign-In-to-MSN-%F0%9D%9F%8F-888-212-3545-Learn-how-to-log-in-to-your-MSN-account-easily-and-start-connecting-with-friends