I have been unable to retrieve the secret key for my REST API app in SANDBOX mode, although it is being displayed when in LIVE mode. I've tested with multiple browsers and on multiple terminals, and the SHOW button is just not responding in sandbox mode. I have also tried creating a new app, but the same issue persists with that too.

Has anyone else faced this issue? Could I have missed some step or requirement? The first app is an old one, created more than a year ago, and I was able to retrieve the secret key and test it sandbox mode then, and it is still working now.

Thank you for your kind attention.