When did Omni stopped?

Can you clarify your question about when Omni stopped? Are you referring to the Omni Layer protocol, which is a decentralized protocol that enables the issuance and trading of digital assets on the Bitcoin blockchain? If so, it's important to note that Omni Layer has not stopped operating. It's an active protocol that continues to be used by developers and users alike to create and trade a wide range of digital assets. However, if you're asking about a specific project or service that utilizes the Omni Layer protocol, it's possible that it may have ceased operations for some reason. If you have more context or details, I'd be happy to provide a more specific answer.