Hey ​@Ian Tiba first check if the you have the correct phone number (one way to test it is to see if you can send a message to the person from your number not connected to Manychat).

If the number is correct, then check this document for possible causes for this: https://help.manychat.com/hc/en-us/articles/15580879039388-Why-WhatsApp-messages-are-sometimes-not-delivered

Also, try with different numbers to see if this happens with all numbers or specific numbers only.

Lastly, your template message is very broad - and may be triggering spam filters.

I’d try a more detailed message (something like ‘Hey, thank you for contacting us. How can we help you today?’), see what happens in this case.