No solution available as EA insist this is a connection issues for user. That's despite loads of players having this issue start at exactly same time
It's happened during Rush, Squad Battles and Draft and even whilst claiming an SBC and once when just in Ultimate Teams got disconnected and returned to Main Menu.
I believe it's a change in their connection protocols which is incorrectly identifying a packet as being lost. I've run packet loss test for 10,000+ pings. No loss but EA's connection report say I have lots!
Spread the word, no-one buy FC26 when it's released in a little over 4 months