WPSSO works great with PHP 7.0 and 7.1.
Could you copy-paste the PHP fatal error message?
Enabling the WordPress debug.log if often the best way to get these errors. See here https://wpsso.com/docs/plugins/wpsso/installation/debugging-and-problem-solving/ for more info.
js.
I looked in the php7.0-fpm and nginx logs. The errors I saw didn’t seem consistent with the activation of your plugin. The point is, it says fatal error at the top of the plugin screen following activation but in conjunction with that error the plugin remains inactive. I have gone to another site, same server and did not in fact receive that error. I believe this was a conflict with another plugin on the site.
Meanwhile, I’m excited already looking at the dashboard and setting wpsso up. I’m into comprehensive seo for clients I think moving forward your suite will be beneficial.
Thanks for taking the time to respond.
Stu