It's set to Active, not Draft, Paused or Inactive.

The start trigger matches what's actually happening. For example, "Subscribes to All Contacts" won't fire for people who were already on the list.

Runs once or multiple times is set the way you want. If a contact has already been through a "runs once" automation, they won't enter again.

Any segment conditions on the trigger match the contact.

Triggers don't work backwards. Customers who met the trigger before you switched the automation on won't be added automatically.

Customers brought in by Sync Contacts or the daily spend update don't start automations. These are bulk imports, and that's deliberate so existing customers aren't all welcomed at once.

New and edited customers from Nomni POS sync one by one, so they do start automations.

Contacts you import from a CSV only start automations if the import's option to trigger automations was left on.

To include existing customers, use a scheduled or date-based trigger, or add a tag in bulk that starts the automation.

They're Active (not unsubscribed, bounced or unconfirmed) on the list the email sends to.

The field the trigger depends on is filled in. For example, a birthday automation needs Date of Birth.

Date-based triggers check once a day at the time you chose, in the contact's or account's time zone. Someone added after that day's check is picked up on the next matching date.