It is difficult to say for sure what might be wrong. I can say that any droplet which is not quite old at this point will only run into issues of this type if something is configured in it’s operating system which might cause it. This is relevant as you may find some old mentions of changing the kernel setting in our control panel, which is outdated information for most cases now.
If you click on the droplet name at cloud.digitalocean.com, you can then click on Recovery on the left side. From there you can set the droplet to boot from our recovery ISO and then power off and back on. When it boots back up you can use our web console, you will see a menu that loads with the ISO. You can mount the droplet’s drive at /mnt with a quick menu option. You can also find SSH login details on that screen which you can use to copy data out of the droplet if need be. This may make it easier to simply move data to another droplet, if you are not sure what caused the issues with the current one. For that job, I like to use rsync:
Of course this droplet can likely be fixed without the need to replace it, but with no certain path it can sometimes be the most cost effective option to simply create a new one.