If you mark a question as mandatory, it means the respondent cannot submit the survey if they have forgotten to answer the mandatory question.
If the respondent clicks the Submit -without answering a mandatory question, an error message will appear asking them to respond to the mandatory question.
To make a question mandatory, select the question and check the “Mandatory” checkbox in the right-hand panel. The question will then display an asterisk to indicate that it is mandatory. Save.
QUESTION: Can I change the warning text in the red box?
No, this cannot be done.