As far as I know, all started with Louise and Zoe not being friends with Sam. They probably never liked him and they have some kind of drama and now, when Alfie and Zoe started getting close, he chose her side.
This is what happened on twitter.
Chai is good friends with Alfie and Zoe and Alfie favourited those tweets. It’s about a Video that Sam made. It made him seem very bad. So, Zoe,Louise,Alfie and Chai we’re against Sam. And the rest of the others just followed.
About Sam and Louis…Everything was perfectly fine before Japan. Sam used to at least facetime with Jack and Finn alot and at least some what keep in contact with the other boys. Cyr, Sawyer,Louis and Sam all went to Japan and i really think something happened while they were out there. Ive heard rumors that Sam got into a fight and Louis didnt stick up for him so that caused a falling out but no one can be sure, being they wont talk about it. But whatever did happen in Japan, it effected Louis and Sams friendship majorly.
That’s all i found out.