Apologize before you explain. Lead with your reasons and the whole thing sounds like an excuse.

Order changes the meaning of identical words. Reasons first and the apology arrives as the conclusion of your defense, so the other person spends the whole time waiting to learn whether you think you did anything wrong. Apology first and the same reasons become context they can actually hear.

Put the plain sentence at the top next time, then stop talking. Explain only if they ask for the explanation, and keep it shorter than you planned. Most people forgive the thing itself faster than they forgive the lawyering.