-ProtonMail (source)Our SSL certificate authority (CA) is QuoVadis Trustlink Schweiz AG, a leading Swiss SSL certificate issuer. Using a Swiss based CA ensures that our CA's SSL infrastructure is not under the control of US or EU government agencies.
cryptostorm is using Comodo as certificate authority. Comodo is based in the United Kingdom and the United Kingdom is a Five Eyes country. Comodo also seems to be one of the most incompetent CA security-wise (along with WoSign and StartCom) (source).
I would recommend switching to a CA that is based in a country with good privacy laws. Iceland has as far as I know no CA that has wide implementation across operating systems and browsers. However, there are multiple CAs that are based in Switzerland, which has privacy laws comparable to Iceland. I'd try getting the same SSL certificate that ProtonMail uses, since it seems to be working great for them.