MyBB Community Forums

My forum is one month old and I've just realized that when I access it, all browsers say that "connection to this site is not secure". 
I didn't do anything bad, I just manually registered several users and posted some threads. 
How can I make my site secure?

that is a normal thing - need not worry much about it unless your site/forum deals with money transactions ..
yet, if you want to make your MyBB forum secure then see Setting up HTTPS guidance

see also replies here

O.K. I was worried. Thanks!