You’ve automated a workflow with Microsoft 365, only to hit a wall with constant permission requests, broken background jobs, and security warnings. Why do custom app integrations feel so much riskier than they should? Today, I’m breaking down the hidden security traps of delegated permissions—and the smarter path almost nobody talks about: app-only permissions in Microsoft Graph.If you want safer, smoother Microsoft 365 integrations that just work, stick around. We’ll tackle exactly where most setups go wrong, and I’ll show you the step-by-step fix that unlocks seamless, secure automation.Why Delegated Permissions Break Your AutomationIf you’ve ever found yourself wondering why your Microsoft 365 automations stall out at the worst possible time, you aren’t alone. Maybe it’s late at night. You’ve set up Power Automate to sync files for accounting, and you think you’re set—but two hours later, that job throws a “please login” prompt or just quietly dies while nobody’s watching. The reason? Most custom apps and automations start with delegated permissions, because—honestly—it feels like the quickest way to get something working. Use a user’s credentials, check a box, and your app instantly inherits whatever that person can do. For a new project, that approach is often tempting. It’s practically encouraged by the UI when setting up flows, bots, or even one-off scripts.But there’s a catch that comes back to bite every single admin who tries to scale this model. Delegated permissions tie your automation to an actual human user. Under the hood, every API call is piggybacking on a real person’s permissions and session. That means anytime the user logs out, gets a new password, or leaves the company, your critical workflow grinds to a halt. The job doesn’t just hit pause; it fails—sometimes loudly with an error, sometimes in silence until someone starts asking about missing reports.Wake up calls usually come early. One morning you discover that automated file upload you tested for weeks suddenly failed at 2 AM. Support tickets pile up. The logs just show “authentication failed,” or sometimes nothing at all because a session silently expired. It’s not just about the inconvenience, either. There’s research showing that 70 percent of custom Microsoft 365 app support tickets boil down to issues with authentication and token handling—not the logic of the app itself. Most of those relate directly back to delegated permissions: session timeouts, invalid tokens, or missing MFA steps.It sneaks up on you in other ways, too. Delegated permissions are persistent headaches when users change roles or go out on leave. Your payroll bot or HR automation? Relying on an account tied to a real person is an accident waiting to happen. Even if you assign a special “service account,” someone’s going to forget the password expiration, or not realize the license is about to be removed. Internal audits end up flagging flows and bots that haven’t run in weeks because nobody even checked that a password needed updating.What’s worse is that the path of least resistance encourages risky shortcuts. Maybe your workflow needs to touch resources across SharePoint, Exchange, and Teams. You keep adding permissions to “make things work”—a little more mailbox access here, site collection access there, until suddenly the user tied to that process has more admin rights than your own IT staff. For the sake of reliable automation, teams sometimes grant global admin status to these accounts. Not because it’s smart, but because delegated permissions force your hand when automation becomes business-critical. That transfer of privilege isn’t theoretical—there are plenty of real-world stories about bots accidentally gaining far too much access because delegated accounts kept hitting permission errors.The cracks keep adding up. Let’s say you run a monthly reconciliation process for Finance. Every month, the Power Automate flow slows down—or worse, fails outright. Why? It depends on a single delegated account that loses its session, has its password changed, or gets flagged by security. Then, a Teams notification pings your admin on a Sunday morning, or a finance report doesn’t get delivered. Fixing these issues isn’t just tedious—it chips away at your confidence in automation altogether. Suddenly, you have to ask yourself: is the time you saved with automation just spent troubleshooting all the new failure points?It gets messier as your organization grows. Scheduled SharePoint syncs, background tasks for compliance archiving, automated chatbots serving HR questions at odd hours—all of them end up teetering on the stability of whichever user account is backing the permissions. Unlike true service principals, users get deprovisioned, their accounts age out, sometimes they leave, and IT is left picking up the pieces. When everything is built on a stack of delegated permissions, small changes in personnel or security policy ripple out and break things you didn’t even realize depended on that one login.On top of the technical pain, there’s always an uncomfortable conversation with Security. If you’re giving broad delegated rights “just to make it work,” you’re setting up a situation where a breach in that single user account compromises not just their inbox, but anything your automated job can touch—in some cases, the entire directory. Mistakes compound. If you’ve got critical reports or financial automations tripping over password resets or license removals, your stakeholders start to ask if automation is worth the risk at all.The frustrating part is that none of this is particularly rare or new. In practice, a massive percentage of custom Microsoft 365 automations fail or stall because delegated permissions seemed easy at first, but break down in anything resembling a real-world scenario. A single user’s password prompt shouldn’t be enough to stop payroll from running or compliance jobs from archiving emails. Yet, that’s often exactly what happens. It’s death by a thousand cuts, and the more ambitious your automation, the more these issues cost you both in time and in security risks.So, if delegated permissions have you managing user accounts like a house of cards, it’s not just you. For service accounts, background jobs, and any workflow that should “just work” without a user present, there’s a better way hiding in plain sight. The question is: are you ready for the approach that actually supports secure, reliable automation—without babysitting logins?Solving the Maze: How App-Only Permissions Change the GameSo here’s what most IT pros wish someone had told them sooner—big organizations don’t gamble critical automations on a user’s password or session lasting the night. They use app-only permissions. It’s not because they have more resources or buy some super-premium Microsoft license. The difference is in how their apps talk to Microsoft Graph: not as Jane from HR, or Tim from Finance, but as a dedicated application identity. This approach means the app itself is recognized as its own entity in Azure AD. No one needs to log in. No one’s credentials go stale. If you need a SharePoint job to run at 3 AM, it doesn’t check if someone’s sitting at their desk—it just works.App-only permissions are kind of the secret sauce behind reliable automation. Once you get this concept, things actually get simpler. The app gets a defined set of permissions—say, access to just the resources it needs on SharePoint, Teams, or Outlook—nothing more. That’s the principle of least privilege in action. Instead of a bot inheriting every permission tied to a specific user (and all the risk that comes with it), your app only gets the exact access it needs to do its job. You get more predictability in what it can access, less exposure if something goes sideways, and no headaches chasing down that elusive “global admin” checkbox just to keep automation running overnight.But here’s why the idea is both powerful and, for most, intimidating: setting up app-only permissions doesn’t come with a one-click button labeled “make this secure and easy.” The interface is scattered across Azure AD, the Graph Portal, and sometimes even the classic legacy admin pages. Registering an app means navigating menus, picking an authentication method, setting the right callback URLs, and ultimately picking permissions out of a dropdown that’s definitely longer than it needs to be. There’s nowhere in the process that stops and explains why some permissions are labeled “Application,” others “Delegated,” or what happens if someone grants too much access. Most tutorials gloss over the messy middle. You’ll see quick demos of setting up client secrets or certificates—but almost none show the aftermath when the wrong permission is selected, or the admin consent process goes sideways.Every admin knows the feeling: you think you’ve set everything up, but the next step throws you a cryptic error. Maybe “Insufficient privileges” pops up when you test the Graph call, or your webhook refuses to fire because consent wasn’t properly granted. Figuring out why can turn into a support ticket scavenger hunt. When you finally track it down, it’s something like “Application not authorized by admin,” which translates to: someone needs to give organizational-level consent before this app can act without a user present. Depending on your tenant’s security policies, that step might involve layered approvals or even a change management process.Let’s play out what happens when you get it right. Your app is now its own service principal. Want to upload documents to SharePoint, even if everyone’s offline or accounts are in limbo? No problem—the bot has the permissions and it never gets kicked out for inactivity. Say you’re running a nightly archive of conversations from Teams to SharePoint for compliance. People can switch jobs, leave the company, or just forget their password over the holidays—your automation keeps running as if nothing changedBecome a supporter of this podcast: https://www.spreaker.com/podcast/m365-show-podcast--6704921/support.Follow us on:LInkedInSubstack

Ver todos los episodios