Every time I attempt to get a pet, it says "Pets are not allowed here!" How do I allow them?

Configuration Wiki: http://github.com/DSH105/EchoPet/wiki/Config.yml#worlds-section

It still doesn't work, I enabled them by default, I assigned them to the right worlds, and they worked... for a couple hours. I don't know what happened please help!

Make sure you spell them correctly and with the appropriate case.