A blank AB Projects tab in Microsoft Teams is rarely an AB outage — it’s almost always the Teams client (stale cache or old version), sign-in and consent, or a network that blocks the app’s domain. Match your symptom below and work down the list.
AADSTS50020, you’re signed into Teams with a personal Microsoft account (like @outlook.com or @hotmail.com) — those can’t use AB at all. Switch to your organization’s account (see Supported Platforms).First, a 30-second triage
| What you see | Most likely cause | Start at |
|---|---|---|
| Blank tab or endless spinner, works for colleagues | Stale Teams client or cache on your machine | Steps 1, 2, 4 |
| Stuck at “signing in”, or a consent popup appeared | Sign-in/consent didn’t complete | Step 3 |
Error mentioning AADSTS50020 | Personal Microsoft account | The callout above |
| Nobody in your whole organization can load it | Admin consent or conditional access policy | Step 3 |
| Fails on the office network, works on your phone’s cellular | Firewall/proxy blocking the AB domains | Step 5 |
| App loads fine but a project or tasks are missing | Not a load failure — membership or filters | I Can’t See My Tasks |
1. Reload the tab or app
Right-click the tab and choose Reload, or close and reopen the personal app from the Teams left rail. A transient load failure usually clears on a reload — always try this first.
2. Update and fully restart the Teams client
AB Projects loads its interface from blz.actionbridge.io inside a Teams webview (an embedded browser window). An out-of-date desktop client can run an old embedded engine that fails to render it.
- Quit Teams completely and restart it (not just close the window), and let it update.
- On Teams in the browser, use a Chromium-based browser (Edge or Chrome).
- Quick check: if AB loads in Teams web but not the desktop app, it’s almost certainly a desktop cache/version problem — go to step 4.
3. Sign-in and admin consent
AB signs you in automatically with Microsoft SSO (single sign-on — it reuses your Teams login instead of asking for a password). A blank panel or a stuck “signing in” usually means that sign-in didn’t complete:
- Allow any consent or permission popup that appears — blocking it leaves the app half-signed-in.
- Make sure Teams is signed in with the correct Microsoft 365 account and organization (see SSO and Microsoft Login).
- Your organization’s conditional access or app-consent policies may require a Microsoft 365 administrator to approve AB before anyone can load it — the telltale sign is that your entire organization is affected while other companies’ users are fine. Point your admin at Why AB Projects Requires Microsoft Graph Permissions.
4. Clear the Teams cache
A stale Teams cache is the most frequent cause of “works for everyone but me on this machine.” Sign out of Teams and back in; if the tab still won’t render, clear the Teams client cache (via your OS) and restart Teams.
5. Network and firewall
The app must be able to reach blz.actionbridge.io (and actionbridge.io). Corporate firewalls, VPNs, proxies, or ad/script blockers that block these domains leave the tab blank. If AB loads off the corporate network — for example on a phone on cellular — but not on it, ask IT to allow the AB domains.
6. App removed or consent revoked
If AB Projects was uninstalled from your organization’s tenant, or its permissions were revoked in Microsoft Entra (your organization’s Microsoft identity admin center), it won’t load until it’s reinstalled and re-consented. Check with your Microsoft 365 administrator.
If none of the above resolves it, contact support and include: desktop or web, what you see (blank, spinner, or an error), and the exact error text if there is any — especially any AADSTS code.