Square Messages Plus Subscribed. Won't send to One of my client's numbers

[UncleRed99]

Hello all, 

I've got a client that I need to send a specific message to regarding an overdue invoice. I know that their number works, as I can contact them via phone, but they seem to be dodging me/no responding thru my personal phone number. I figured I'd make a final attempt by sending a warning thru the square messages plus option. I have not used this specific number for this client to send invoices/estimates, as their son provided his number for that. 

So, what I did was changed the contact number to the known number I had in my cell for this individual, and then attempted to send a message using my msgs. plus number. (This client is using an iphone if that matters, as from my cell it sends/receives iMessages from this number) When attempting to send a message, it's immediately highlighted in red with a "Failed to Send. Retry" stamp at the bottom of the message bubble. What could be going wrong here...??? 

[MayaP]

Hello @UncleRed99 I am sorry you are having issues with getting ahold of your customer to pay the invoice, I know that can be frustrating. We’ve made a few updates to Square Messages to minimize potential disruptions in the future. These communications will now be dependent on your customers starting the conversation by replying to service messages, like a receipt, appointment reminder, or order update, just to name a few. We’re also working to re-enable unrestricted outbound messaging capabilities early next year. We know and understand how challenging service disruptions can be and we apologize for any inconvenience.

I am sorry for any confusion. If you need anything else let us know!