It could be a validation rule or a necessary field that was introduced in production but not in the sandbox. There can be an issue with some integration. It's possible that the action calls anything from a managed package invisibly, and you don't have a license in use. It's possible that anything is lacking from the action's check of your user's Role/Profile/permissions. It's possible that some reference data is lacking. A flow/process builder that is deployed but not activated from the sandbox.
There are some tools that can be used to compare two surroundings (Gearset, OwnBackup...) Alternatively, if you're a developer, you may use sfdx/vscode to download the projects and compare them with Winmerge.
Hope this helps!
Check out Salesforce admin certification today.