When there is a startup without a local MySQL or PostGreSQL service, the service fails to connect to the remote database.

Please change the /usr/lib/systemd/system/fusionauth-app.service After list to include network.target:

[Unit]
Description=FusionAuth App
After=network.target mysql.service postgresql.service fusionauth-search.service

I'm running the service on a different machine than the database and this will ensure the fusionauth-app.service always starts properly.