Overview

A calendar campaign reaches prospects through Google Calendar invitations. Tantra creates an event on your sender's calendar, then adds recipients as attendees in stages. Google sends the invitation email when each attendee is added.

The most common reason a campaign "looks stuck" is not a fault. Invitations go out in daily batches, so a new campaign does not send to everyone at once. This article walks through that and the other real causes.

Likely causes

The campaign is still sending in batches. Recipients are added in groups of up to 200 attendees, roughly 24 hours apart, so early batches send while later ones wait.
The campaign was never started. A campaign in draft does not send anything.
The campaign is scheduled for a future time and has not reached its start time yet.
The campaign is paused.
No connected sender is available, so Tantra cannot create or update the calendar event.
The event start time has nearly arrived, so Tantra stops adding new attendees.

How batching works

When you start a campaign, Tantra splits your contacts across your senders and stages them into batches. A background process checks for due batches every few minutes and sends the next batch when its scheduled time arrives. Standard batches are capped at 200 attendees and spaced about 24 hours apart. Within a batch, invitations are added with a short random delay between each one to stay under Google's limits.

This means a large list can take several days to finish. That is expected and protects your senders' deliverability. There is no per-day invite ceiling that silently blocks sending.

Step-by-step checks

Open the campaign from Campaigns and check its status badge. If it reads draft, open the campaign and start it.
If the status is scheduled, confirm the scheduled start date and time. Invitations begin at that time, not before.
If the status is paused, resume it. Batches only run while the campaign is active.
Open the Contacts tab on the campaign. Contacts already invited show a Calendar Response badge of Yes, No, or Awaiting. A growing count of Awaiting rows over the next day means batching is working.
Confirm at least one sender is connected. Go to Accounts and check that the sender used by this campaign shows a green Connected badge. See Reconnect a disconnected sender if it shows Disconnected.
Check that the event start time is still in the future. Once the event time passes, Tantra stops sending invitations for it.

What happens next

After you start a campaign, the first batch is processed right away. Every batch after that is picked up automatically within a few minutes of its scheduled time. Watch the Contacts tab over the next 24 hours. The Awaiting count should rise as each daily batch adds more attendees. You do not need to keep the page open.

Troubleshooting

Symptom	Cause	Fix
Only some recipients received an invite	Batching is staged in groups of up to 200, about 24 hours apart	Wait for the next daily batch. Check the Contacts tab for rising Awaiting counts.
No invites at all, status is draft	The campaign was never started	Open the campaign and start it.
No invites yet, status is scheduled	The scheduled start time has not arrived	Wait until the scheduled time, or reschedule to a sooner time.
Sending stopped mid-campaign	The campaign is paused	Resume the campaign so batches run again.
Nothing sends and the sender is flagged	The sender shows Disconnected, so no event update can be sent	Reconnect the sender, then let the next batch run.
Invites stopped as the event approached	Tantra stops adding attendees just before the event start time	Use a later event start time for future campaigns so batches have room to finish.

FAQ

Why did not everyone get the invite at once? By design. Invitations are added in daily batches of up to 200 attendees to protect deliverability. A large list finishes over several days.

Is there a daily cap that blocks my calendar invites? No. Calendar sending is paced by batch size and timing, not a hard daily invite quota. Account settings only affect how contacts are split across senders at creation time.

How long until the next batch sends? Due batches are picked up automatically within a few minutes of their scheduled time, which is roughly 24 hours after the previous batch.

My campaign says active but nothing moved. What now? Confirm the sender shows Connected on the Accounts page and that the event start time is still in the future. Both are required for a batch to send.

Can I speed up sending? Adding more connected senders spreads contacts across more calendars, so batches complete sooner. The 24 hour batch spacing still applies per plan.

What does the Awaiting badge mean? It means the recipient has been invited but has not yet responded to the calendar invitation. It confirms the invite was sent.

My calendar campaign is not sending invites