The next step I took was to contact support Viserbank, and it turned out there I was told to top up $50 first to get an OTP number.
I don't know who else to ask if not this forum, is it a scam, or is the mechanism like that? For those who have used Viserbank for transactions, please explain, sir.
I also just tried accessing it and as WillyAp said, it's offline. But this alone is enough to show that this is most likely a scam, it is an old scam that has been around for a long time. And as you said you transferred money to that wallet? I'm really sorry, you lost your money and there's no way to get it back.
What I'm more curious about is that from your profile, you've been in the market since 2017, which means you're not an inexperienced newbie. I don't believe that someone with as much experience in the market as you could fall into these traps so naively. Besides transferring money, how can you easily give your identity to unfamiliar websites you've never heard of? Why don't you do your research or ask someone for help before doing KYC or transferring money?