Hi there. This looks like an error that often happens with WordPress.com blogs that have their own domains. WordPress.com can't issue security certificates for every site that has a custom domain, so your browser will sometimes give a warning when you try to visit that site, as that domain doesn't match the security certificates for WordPress.com. If you change the URL from https://thoughtsandthings1.com/2015/04/25/200-followers-giveaway-thank-you/ to http://thoughtsandthings1.com/2015/04/25/200-followers-giveaway-thank-you/ (i.e. remove the "s" in "https") then you won't see that error. And if your browser gives you the option, it's also safe to set this site as an exception, then it won't be blocked for you again.
You won't be able to change the actual links in the reblog, so your readers might still experience this problem. You can perhaps give them the explanation I gave you via a comment on that reblogged post of yours.
