Locate the lost enquiry
Submit an approved test request with a unique tag. Check the browser request, handler response, mail service log, or CRM API result. Don't start by randomly replacing the plugin: separate validation, antispam, server sending and recipient delivery first.
Continue with: Website leads in SalesDrive: field mapping and acceptance.
Check the sender settings
Check recipient address, sender domain and mail service configuration. SPF, DKIM, and DMARC must match the actual sending method. The visitor's address is usually used to reply, not as a spoofed domain sender. For CRM, check the token, rights, required fields and clear API error handling.
Continue with: Website monitoring: why HTTP 200 is not enough.
Eliminate silent failures
The form must show the correct result and not hide the undelivered enquiry. Agree to secure log or backup storage with limited access and retention period. Check for retapping, weak network, and external service failure. After the fix, confirm that you actually received the request, not just the button text change.
Is it enough to install the SMTP plugin?
It changes the transport, but doesn't fix form errors, bad recipient, DNS authentication, or CRM integration. End-to-end verification is required.