We noticed that you have tried to add a number to a messaging service associated with a US A2P 10DLC Sole Proprietor campaign. Please note that all Sole Proprietor campaigns have a max limit of 1 phone number per campaign. Since you have reached this limit previously, your phone number could not be successfully registered for US A2P 10DLC. If you try to send SMS or MMS messages to the US using this phone number, those messages will be considered as unregistered traffic, where higher fees apply.
You already have 1 phone number registered with your Sole Proprietor campaign.
You may continue to send messages to other non-US destinations using this phone number. However, if you want to use this phone number to send to recipients in the US, please consider removing all senders from this campaign from the Messaging Services page and then add back the number you wish to use, or register for a standard A2P brand and campaign instead.