How to Share a Calendar With External Users Without Requiring a Microsoft Account
Microsoft 365 calendar sharing requires recipients to have a Microsoft or Exchange account. If your external clients, vendors, or contractors use Gmail, a non-Microsoft email, or simply don’t have an M365 license, they can’t access your shared calendar — unless you use a tool that supports anonymous link-based access. This is one of the most common collaboration walls teams hit when working across organizations. You set up a project calendar in Outlook or a Microsoft 365 Group, you invite your client, and a day later they email back: “I can’t open this.” Behind the scenes, Microsoft is checking whether their address belongs to a tenant, has a guest record, or is licensed. If the answer is “no” to all three, the door stays closed. ...