ok now that you have switched to vultr, let’s actually try and fix the issue, rather than jumping around to different hosts every time.
post any errors you see in your terminal here - copy the entire output of whatever you see and paste it here inside backtics like this
we need to see your entire app.yml file.
cd /var/discourse
cat containers/app.yml
paste the entire output inside triple backtics like above, but remove the password strings (keep the quotes you are using around the passwords so we can make sure they are correct along with other syntax).