Can a company not fulfill the buyback promise?

I'm curious about the dynamics of stock buybacks and how they work. Specifically, I'm wondering if a company is legally allowed to choose not to fulfill a buyback promise it made previously.

I understand that buybacks are often seen as a way for a company to return capital to shareholders and signal confidence in its prospects. However, are there situations where a company may decide not to go through with a promised buyback? What are the legal and financial implications of such a decision?

I'd appreciate any insights or examples of when this might occur. Additionally, if there are any regulatory or legal factors that influence a company's ability to fulfill a buyback promise, I'd like to learn more about them.

Thank you for sharing your knowledge!