Unfortunately, Giphy decided to start charging for access to the image emoji - and the amount they were asking was ridiculous.
For a short term solution I swapped it out with Tenor, but it's not the best technical implementation. For example, it won't automatically theme the gifs around your custom emoji at the moment.
Hopefully I can change that in the future, but I wanted a quick replacement in place first.
Edit: Please note that if you are using Giphy images as chat bot responses, you will need to remove them or swap them out with a Tenor image instead.