[AC Question]

Samsung galaxy s6 phone is limiting length of messages from some contacts....why?

[Rukbat]

Text is limited to 140 octets, or 160 ASCII characters (or 80 Unicode characters). That's not your phone, that's text message protocol. If you don't allow either multiple text messages or MMS, there's nothing the phone can do but chop the message short. (Multiple messages chop them into 160 character messages and sent them one at a time. MMS puts the message innto a text file and sends a link to the file on your carrier's server.)