Yes, for martingale to actually work there is two condition to be fulfill which is infinite bankroll and also infinite win amount (theoretically) because you will need infinite amount of losses as well and since you have infinite bankroll this means that you will never lose at all because you have infinite tries

Unfortunately both condition is unreal because you cant have an infinite bankroll and all sites have their maximum win amount . At one point if you keep on losing then you will hit the max win amount limitation on the site and you cant continue to double up your wager amount

For references, most sites has a max win of 20 BTC or so