Sherbet uses same oddsprovider as some other sportsbooks that many players have had bad experiences lately (bc.game/rollbit/owl.games/etc.) according to what I've been reading on here, twitter and trustpilot. This oddsprovider is very actively flagging accounts that are placing good bets (value bets) and/or accusing players of arb abusing or syndicate betting.
I would really suggest to avoid sportsbooks using this oddsprovider for the time being, decent risk of your winnings being confiscated.
That's right, these are dirty criminals. I also play volleyball bets very successfully and many of the sites immediately limit, that is, the provider.
Of course, the provider has no such rights, he is doing illegal activity. But these sites consist of 2-3 people and they have no choice