Can't reach - 404 - my deployed Spring Boot App on DigitalOcean Droplet

Question

I deployed a simple app to test it, I've succeeded in deploying it and it runs normally. But When I try accessing it responds with 404.

After I run it

When I try to access http://<MY_IP>:8888/ or http://<MY_IP>:8888/cayan, I get

Am I missing something?

Thanks & Appreciate your kind help.