When a Microsoft app on iPhone asks for a CAPTCHA but it won’t load, keeps spinning, or loops back after you solve it, the problem is usually cookies/tracking controls, network filtering, or a WebView that needs a reset.

Padlock tangled in string symbolizing a stuck verification step

Start with the quick checklist below (most fixes take under 3 minutes), then go deeper if it’s still stuck.

1. Quick checklist (do these first)

  • Switch networks: try cellular data instead of Wi‑Fi (or the other way around).
  • Turn off VPN / iCloud Private Relay temporarily (they can break challenge pages).
  • Force-quit the Microsoft app and reopen it.
  • Restart your iPhone (clears stuck WebView sessions).
  • Update the app (App Store) and update iOS if an update is pending.
  • Try “Use a different sign-in method” if shown (Authenticator prompt/SMS/email).

If the CAPTCHA appears but fails over and over, jump to section 4.

2. Rule out network filtering (the most common hidden cause)

CAPTCHAs often load from third-party security domains. If your Wi‑Fi uses filtering, a “safe DNS,” or an ad blocker, the page can load partially and never finish.

Network filter blocking signal waves

  • Disable VPN in the VPN app or in iOS Settings > VPN (if present).
  • Disable iCloud Private Relay (if you use it): Settings > Apple ID > iCloud > Private Relay.
  • Check DNS/filtering profiles: Settings > General > VPN & Device Management. If you see a DNS or filtering profile you don’t recognize, disable/remove it temporarily (only if you know it’s safe to do so).
  • Pause content blockers if you use a system-wide ad blocker with VPN/DNS mode.
  • Test on cellular for one login attempt—if it works there, your Wi‑Fi network is the culprit.

Once you’re signed in, you can re-enable protections one by one to see which one breaks the CAPTCHA.

3. Fix Safari/WebView settings that can block CAPTCHA

Many Microsoft apps open sign-in inside an embedded Safari (WebView). If Safari is blocking cookies or cross-site tracking too aggressively (or an extension is interfering), CAPTCHA widgets can fail.

  • Go to Settings > Safari.
  • Temporarily turn off Prevent Cross-Site Tracking.
  • Temporarily turn off Block All Cookies (if it’s on).
  • Scroll to Extensions and temporarily disable any content-blocking extensions.

Try the sign-in again in the Microsoft app. If it works, turn settings back on afterward and keep only what doesn’t break sign-in.

4. If the CAPTCHA loads but never accepts your answer

This usually points to time/device checks, repeated failed attempts, or “dirty” session data.

Reset symbol with circular arrow and eraser

  • Check Date & Time: Settings > General > Date & Time > turn on Set Automatically. Incorrect time can cause validation failures.
  • Stop retrying for 10–15 minutes if you’ve failed several times. Repeated attempts can trigger stricter challenges.
  • Try a different connection (cellular vs Wi‑Fi). Some IP ranges are flagged more aggressively.
  • Use a different verification method if offered (Authenticator push, SMS, email). This can bypass the CAPTCHA path.
  • Sign in from Safari directly (temporarily): open Safari and go to the Microsoft sign-in page used by your service (for example, the URL your app launches). If Safari succeeds, return to the app and try again.

If it only fails on one account but works with another, the issue may be account-specific (section 6).

5. Reset the app’s sign-in session (without guessing)

Sometimes the CAPTCHA loop is caused by a corrupted sign-in session inside the app.

  • Sign out of the app (if you can reach settings/account).
  • Force-quit the app.
  • Reopen and sign in again.

If you can’t get far enough to sign out:

  • Offload the app (keeps documents/data in many cases): Settings > General > iPhone Storage > pick the Microsoft app > Offload App, then reinstall.
  • If offloading doesn’t help, delete and reinstall the app (only after confirming anything important is synced/backed up).

This forces a fresh WebView/auth session and often clears a stuck CAPTCHA state.

6. Check for account/security flags (when nothing else works)

If Microsoft thinks a sign-in is risky, it can keep escalating challenges (more CAPTCHAs, more loops), especially if you’re traveling, on a new device, or using privacy-routing features.

  • Try signing in on another network and device once (even a computer). If it works there, the iPhone/network combo is being challenged.
  • Review security activity for your Microsoft account and confirm recent sign-ins are yours.
  • Reset your password if you suspect you’re stuck in a risk loop due to unusual activity.
  • Avoid rapid retries; wait between attempts so you don’t trigger rate limits.

If you’re using a work/school account, your org may enforce extra checks that affect embedded sign-in pages—your IT admin can confirm.

Final thoughts

Start by changing networks and disabling VPN/Private Relay, then check Safari cookie/tracking settings—those two areas fix most iOS CAPTCHA loops in Microsoft apps.

If it’s still stuck after a clean reinstall and a different network, it’s likely an account or policy flag, and signing in successfully once on another device often “unsticks” the challenge chain.