Thank you very much for your response.
I think I will stay with ViaBTC as it was the only one that opened properly.
Viabtc is a good pool, however, using only the fact that stupid firefox opened that without an issue unlike the rest of the pools is a terrible idea, it should not be your point of judgment, most browsers and security applications are stupid and paranoid over anything crypto.
Did you try a different browser?
No, I tried only FireFox. I trust it because it is also open source. Should I try with Chrome & Edge, or something else?