Would love feedback on my new site (inc why it seems to trigger some places' network security).

Hello all, I'm new here - I just made my new site, www.davidgange.com , live a couple of days ago (intended to showcase my writing & photography, & hopefully attract the interest of the artists etc I often collaborate with). I'd love some general feedback - particularly if you see anything that isn't quite working. But in particular, I'd love to know if anyone has any ideas why something unexpected is happening:

I tweeted about the site yesterday, and straight away had several people letting me know their workplace network security was blocking it (mostly from universities, which is a bit of an issue since many of the people I'll be trying to reach are university employees). Today was the first time I've been able to try my site from a business network instead of my home wifi, and the same happened. I've attached screenshots of the error messages. Everything on my site - SSL etc - seems to be in order. So I was wondering whether anyone else had experienced this, or had any idea of why it might be going on? Any ideas much appreciated - thankyou! David.

The SSL is fine to me, show Secure here (Windows/Chrome). You try checking again