“Ларавел добавляет много ко многим” Ответ

Ларавел добавляет много ко многим

You should pass an array of user IDs to the attach() method.

For convenience, attach and detach also accept arrays of IDs as input

Change your code to:

$team = \App\Team::findOrFail($request->team_id);
$team->teamMembers()->attach($request->members_id);