Looks OK to me, including in https.
Standard Let's Encrypt type certificate (a free service but only lasts 3 months at a time rather than far longer of other places, quite often then expired certificates are this if the web dev has not gone and pressed renew).
Usual first step is check your clock on your PC -- if it randomly decided to go back a year or something it would have the certificate appear out of date.
After this then year we are looking at things like your machine having a nice virus attempting to redirect traffic for you, your router/work/whatever trying to redirect traffic badly or your web browser not accepting Let's Encrypt as an authority.