Hey, folks
I wanted to see if this worked for anyone else. Sometimes, we get the error "An unknown error has occurred." It is so generic that it could be caused by many things.
See if the following helps:
When you enter ranked squad, prepare quickly before the error sign shows up. When you do that, the error sign should still be on the screen.
Now, don't click anything after you have already readied up, with the error still on the screen. Let the game load by selecting your position for you, all while the error message is still on the screen.
Now, once it has selected your position for you automatically, the game will load you and your team onto the field, and boom, the error message is gone for good. If it ever comes up again, the same thing: ready up fast before the error message shows up and let it select your position for you without clicking off the error message.
Once it loads onto the field, the error message is gone. Because of it, I was off the game for two months. You just have to be patient, that's all.