Internationalization: Not loading plugin translated text

I just found it, it’s because I missed placing the text domain in ” in my php code.

It should be

__('Read More', 'my-custom-dragon-plugin');

instead of

__('Read More', my-custom-dragon-plugin);

Now my translation is working. I am just wondering now if it is possible to use a custom text domain instead of my long plugin slug.

I was able to figure it out before I saw @mat ‘s answer. I upvoted your comment though @mat.