The error code is obsolete. Find more information in the changelog.
You provided the MaxPrice parameter in your API request. MaxPrice will prevent a message from sending if it exceeds the price you specified.
Please note that SMS pricing is per-segment. SMS messages longer than 160 characters (or longer than 70 characters, if emojis or special characters are used) will require multiple segments. For a detailed explanation of message segmentation and encoding, see What the Heck is a Segment?.