Hi, thanks for all the help here, but unfortunately I’m afraid I can’t provide the error message as within a day I posted here (I also sent another email to squarespace team at the same time) I was informed by squarespace team via email that my cert suddenly started working after months of attempt without any mention of what was the error message/code.
I’m still wondering what has been bugging my domain but looks like it’s not an answer I’ll ever get from them, but I’m happy enough that it’s working now. Definitely appreciate all the help here.