Well I have the same thing on my side … Some thread on the internets tell it might be related to having long domain names ?
I don’t really understand how that has anything to do with 3.8 
Anyway, if you want you can try to increase the parameter to 128 using 'nano /etc/nginx/conf.d/ssowat.conf' then edit the file and use Ctrl+X to save (confirm with Y + Enter)
Then try again nginx -t to validate that nginx is happy, and if yes, systemctl restart nginx