Troubleshooting

Quick fixes for the messages and states you see in the add-on.

Dialog will not load

Could not reach the MailG API

The start dialog could not call the MailG backend.

• Confirm you are online
• Marketplace installs: wait a moment and reopen 🚀 Start
• Self-hosted: check Apps Script properties APP_URL (public HTTPS) and APP_API_KEY
• The add-on cannot use localhost — use a tunnel for local API testing

Could not read your sheet

MailG failed to read the active spreadsheet.

• Make sure a sheet tab is open (not only the Apps Script editor)
• Reload the spreadsheet, then reopen the dialog
• Confirm you have edit access to the file

Loading… never finishes

Close the dialog, refresh Sheets, wait ~15 seconds for Extensions, then 🚀 Start again.

Empty sheet

No email address found in your sheet

MailG needs at least one column with valid email addresses.

• Add emails under a header, or click Fill with mock data
• Mock data creates Email, First Name, Last Name, Company and often My First Template

See Start dialog tour.

Templates

• Create: Creating Template... → Template created successfully! or Failed to create template! Try again later.
• Update: Updating template...
• Delete failures: Failed to delete template. Try again later

See Templates.

Sending problems

Send button disabled / Send emails with no count

• Select a Template
• Select a Recipient column with valid single emails per cell
• Guard toasts you may see: Configure your recipient column first, Select a template first., No valid recipient emails found in the selected column.

Campaign fails to start

Toast: Failed to create campaign. Please try again.

• Retry once
• Check Daily quota is not 0
• Confirm API connectivity (see above)

Rows show ⚠️ Failed

That row hit a send error (invalid address, Gmail rejection, transient quota, etc.). Fix the data and start a new campaign for remaining rows, or see Stopping a campaign.

Test email fails

• Configure your preview first — pick template + recipient so preview has a To
• Failed to send test email. Please check your email settings. — re-authorize Gmail if needed, then retry

Tracking

• Opens need remote images loaded by the recipient
• Run 🔄 Refresh Tracking — expect Tracking info synced or No active campaigns
• Status 👀 Opened only appears when the pixel loads

See Email tracking.

Quota & branding

• Sidebar N left is min(MailG remaining, Gmail remaining)
• Free @gmail.com is often capped near 500/day by Google even on Professional
• Watermark still there after pay → checkout email must match Sheets account; reopen the dialog

See Daily quota & reviews and Remove branding.

Schedule did not defer

Times less than about 15 seconds ahead are treated as an immediate send (🚀 column), not a deferred 🗓️ schedule. Pick a time further in the future.

Still stuck?

Full FAQ: FAQ · Email [email protected] · Site app.mailg.io/help