Fix "Page Not Found" Issue on facebook and instagram

I’m experiencing an issue that needs urgent attention. My website links on both Facebook and Instagram have been resulting in a "Page Not Found" message since 2 days - it was working fine when typing manually on chrome.but when i pasted the link on social media it says page not found especially on mobile.
you can look at it on mobile
website - veggieexpress.online
instagram - veggieexpresshyd

The project involves:
- Identifying the root cause of the issue.
- Providing an effective solution to restore the functionality.
- Testing the solution to ensure it fixes the problem, with no adverse effects.

Ideal expert in this case should have:
- Extensive prior experience with website debugging and fixing broken links.
- Knowledge in Instagram and Facebook platforms’ operation regarding the linking system.
- Proactive communication to provide updates on project progression.

I anticipate swift resolution, given the issue's potential impact on my online presence.