Troubleshooting

Common issues and exact fixes.

Installation Issues

"Windows protected your PC" SmartScreen warning

Normal. MP Poster isn't code-signed (yet). Click More info → Run anyway. We're working on a signing certificate to remove this in a future release.

License key validation failed during install

Causes:

Typo in the key — copy-paste directly from email, no spaces.
Key already bound to another machine — email support to reset.
License disabled or expired — check your account page.
No internet during install — installer needs to phone home once.

"WebView2 not installed"

Installer auto-downloads WebView2 runtime. If that fails (corporate firewall, no internet), install manually:

Download from Microsoft → run → 30 sec → re-run MP Poster installer.

Launch Issues

App doesn't open when I double-click the icon

Open Task Manager → Details tab.
Look for python.exe or pythonw.exe. End all of them.
Re-launch MP Poster.

If still no window: check Task Manager — is pythonw.exe running? If yes, window is hidden somewhere (try Alt+Tab). If no, the app crashed silently. Run from PowerShell to see error:

cd "C:\Program Files\MP Poster\app"
..\runtime\python\python.exe launch_window.py

Paste any error to support.

"Port already in use" error

Another process is on port 47821. Kill it:

for /f "tokens=5" %i in ('netstat -ano ^| findstr :47821 ^| findstr LISTENING') do taskkill /F /PID %i

Facebook Login Issues

Browser opens but immediately closes

Usually a session-state bug. Solution:

Accounts → the account → Clear Session.
Click Login again.
Sign in fresh.

2FA code not arriving

This is on Facebook's side, not us. Try:

Wait 60 seconds and click "Resend code"
Switch to authenticator app instead of SMS (more reliable)

"Suspicious login activity" warning

Facebook saw a login from MP Poster's Chromium and flagged it. Complete the verification (usually a security question or code). Once verified, Facebook trusts the session.

Posting Issues

Job stays "Queued" forever

Background scheduler may have crashed. Restart MP Poster — closes window, kills processes, re-launches. Queue picks up automatically.

Listing posts but price is wrong

Make sure prices in your CSV are pure numbers — no $, no commas, no currency symbols. 15999 not $15,999.00.

Photos missing on posted listings

Check the vehicle in MP Poster → Manage Photos. If empty, the import didn't grab them. Re-import with the photo URLs/files included.

Account status went to "Blocked"

Facebook flagged the account. See Account Safety guide for recovery steps.

License Issues

"License is bound to a different machine"

You're trying to activate on a new PC. Email support — we reset the binding so you can re-activate.

"License expired" but I'm subscribed

Stripe payment may have failed. Check your email for "Payment failed" from Stripe. Update payment method at your account page.

"Could not reach license server"

Check internet. If your network blocks our server, contact your IT admin to whitelist *.up.railway.app.

Performance Issues

MP Poster is slow / uses lots of RAM

Each posting job spins up a Chromium browser (~500MB). 3 simultaneous jobs = ~1.5GB. Reduce concurrent jobs in Settings → Max Parallel Jobs (default: 3).

Disk space filling up

Old screenshots and session data accumulate. Clear old data:

%LOCALAPPDATA%\MP Poster\screenshots\

Still stuck?

Email support@mpposter.com with:

Your MP Poster version (Settings → About)
Windows version
What you were doing when it failed
Any error message (screenshot or text)

We respond within 4 business hours, often faster.

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