In order for an SMS message to be sent via PaxFlow you must have purchased SMS quota to send SMS messages via PaxFlow. One message part requires you to have an allowance of 1 credit or higher in order for the message to be sent.

You can purchase the SMS quota in PaxFlow under Settings > Subscription and Billing.

One message part can contain up to 160 alpha numeric characters. Messages containing non-alpha numeric characters will limit the number of characters allowed in a single message part. Messages containing non-alpha numeric characters that exceed the limit of a single SMS message part will be delivered as a multi-part message. Your quota allowance must cover the number of message parts you are sending to.

Please also note that there might be other limits regarding sending SMS messages via PaxFlow.

Check this article for a list of countries that SMS messages can be sent to via PaxFlow:

https://help.paxflow.io/en/articles/8970442-supported-countries-for-sms-messages