Rule reminder
'Prima che' (before) always requires the subjunctive. Other temporal conjunctions like 'dopo che' (after) and 'quando' (when) normally use the indicative, but 'prima che' is unique because the action it refers to has not yet occurred at the time of the main action — making it inherently uncertain.
Make sure you proofread the email before you send it. Choose the correct form: 'Assicurati di rileggere l'email prima di _____.' (same subject)