Improve default error message on form submission failure

[tabuna]

On the default screen, when a form fails to submit to the server, the current message is:

"Please check the entered data, it may be necessary to specify in other languages."

This is confusing because it’s unclear what “other languages” refers to. It feels like leftover text from an old implementation and doesn’t reflect the real issue — the action never even started.

I suggest simplifying it to something like:

"Unable to start action. Please check your input and try again."

This makes it clear right away that something went wrong and the user needs to check their input, without any misleading references to languages.