Sending says Test mode.

Messages wait until your WhatsApp is connected, then go out from your number. Link your number to switch Delivery to Live.

I removed Timeo from Linked devices on my phone.

That disconnects Timeo. Tap Connect WhatsApp and scan a new QR code.

Timeo records every automatic WhatsApp it tries to send and why any did not go. Start with the send history, then fix the cause it names.

Open Settings > WhatsApp and check the Connect your WhatsApp card says Connected.
If it says Not connected, tap Connect WhatsApp and scan the QR again from WhatsApp, Settings, Linked devices, Link a device.
If the connection seems stuck, tap Restart connection and scan again if a QR appears.
Check Automatic messages under Status is on, and the message you expect is switched on.
Scroll to Send history (tap See all for more). Each message shows Sent, Waiting to send or Not sent with a reason.
Fix the reason shown, then send yourself a test with Send test.

WhatsApp not connected: link your number again.
out of message credits: the 500 automated messages for this month are used up. Appointment reminders still go out; other messages resume next month.
the customer opted out: the customer switched off these messages. Respect their choice.
no valid phone number: fix the phone number on the customer record, with the country code.
this message is turned off: switch it on in Settings > WhatsApp.
too many messages at once, try again later: the Messages per customer a day limit was reached.

Nothing until the message is sent; once fixed, new messages arrive from your business number as usual.

Sending says Test mode.: Messages wait until your WhatsApp is connected, then go out from your number. Link your number to switch Delivery to Live.
I removed Timeo from Linked devices on my phone.: That disconnects Timeo. Tap Connect WhatsApp and scan a new QR code.