Invoice and email delivery issues

Symptom: you sent an invoice but the client says they did not receive it.

Fix steps: (1) Confirm the client email address in the Clients section — typos are the most common cause. (2) Ask the client to check their spam or junk folder. (3) If using custom SMTP, go to Invoice Settings and run the SMTP connection test to confirm credentials are still valid. (4) Check your email provider's sent folder to confirm the email was dispatched from your SMTP server. (5) If using default sending, the invoice may have been delayed — wait 5–10 minutes and ask the client to check again.

Symptom: saving SMTP settings shows "authentication failed" or the connection test fails.

Cause: most commonly caused by: wrong password (especially after a recent password change); using your main account password instead of an app-specific password; or wrong SMTP host address.

Fix: (1) For Gmail: generate a new App Password in your Google Account security settings and use that instead of your Gmail password. Your normal Gmail password will not work. (2) For Outlook: ensure SMTP AUTH is enabled in your Microsoft 365 admin settings. (3) Verify the host address exactly matches your provider's documentation.

Symptom: clients find invoices in their spam or junk folder.

Cause: email providers classify incoming messages as spam based on sender reputation, authentication record alignment, and content analysis.

Fix: (1) Configure SPF, DKIM, and DMARC DNS records for your sender domain. Without these, most modern email providers will flag or reject your messages. (2) Keep your sending domain reputation clean — do not send to invalid or bouncing addresses repeatedly. (3) Use a consistent from name and address — changing these frequently is a spam signal. (4) For Gmail delivery specifically, ensure the from address matches the domain with configured authentication records.

Symptom: a schedule ran but one or more clients did not receive their invoice.

Fix steps: (1) Open the schedule send history and check the delivery status for the affected client. (2) Verify the client has a valid email address in the Clients section. (3) If the status shows "failed", check the SMTP connection is active and re-send manually. (4) If no send attempt appears in history for a specific client, verify the client is still listed as active in the schedule configuration.

Symptom: the client received the invoice email but the PDF attachment is missing, empty, or corrupted.

Cause: PDF generation failure during the send process.

Fix: open the invoice in Numwisely and use the manual download/preview function to regenerate the PDF. If the PDF generates correctly from the UI but fails in email, this may indicate a rendering timeout on large or complex custom templates. Simplify the template or contact support with the affected invoice ID.