Fixes for the most common problems.
First, run Settings → Setup → Health check. It tests your NMI connection, checkout, webhook, email and background jobs, and says what to fix.
The dashboard says it cannot reach NMI
Check the private key has API permission and matches your account type (live or sandbox), and that the gateway address is right. Resellers sometimes use their own address.
Card fields do not appear in Take payment
Paste your public tokenization key in Settings → Setup (Card entry). Make sure it is the Tokenization key, not the Checkout key.
Chargebacks do not show up
Add the NMI webhook (Settings → Alerts → Webhook builder) and paste its signing key. Chargebacks only arrive through the webhook.
Customers did not get their emails
WordPress email is often blocked. Install an SMTP plugin such as WP Mail SMTP and send from an address on your own domain.
Background jobs are not running
They run when your site has visitors. On quiet sites, ask your host to set up a server cron for wp-cron.php.
The page shows code instead of the dashboard
A caching or optimisation plugin changed the page. Exclude the dashboard page from optimisation, then clear the cache.
Still stuck? Contact support and include what the health check says.