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?
I tried on FireFox on my Apple laptop for
https://solo.ckpool.org/, and it worked, so I guess my antivirus (from the company I work for) blocked it.
So your suggestion would be to use this one instead of ViaBTC? By the way, for ViaBTC I found this URL:
www.viabtc.com, which is not like the other ones I saw ... Do you have by chance the "real" URL towards ViaBTC please?
Thank you again