I just tried doing that with alby today, before they shut down their custodial wallet. I was able to move all but 15 sats off of it. I think each wallet has their own rules for that, but when i tried moving the last few sats it said the amt did not meet minimum amt, so i gave up. Never messed with wos much though. You might try moving smaller amts at a time. Today with alby i tried moving the balance all at once, but didnt work (a few thousand sats). Then i tried moving smaller amts, which worked till it got down to 15 sats. Thats all i know about it.