502 Bad Gateways are generally errors related to communications to your website. The only time I have encountered a 502 is when I first set my site to HTTPS using and SSL cert. I was getting a 502 until the server/site "synced" up and it resolved itself. 

Is your site running SSL? Is the cert still valid? Reload not working?

You mentioned you only upgraded 2 templates. Normally, if you are upgrading your site via Studio > Dashboard, it will trigger the update for ALL available modules. How are you just updating 2 templates? 

 

No Chris i did upgrade everything, while i was testing and switching templates i realized that those 2 were given me that error message, so i disabled those 2 until it gets resolved bro