Does D&O Cover Breach of Contract?

Usually not. A dispute over unpaid invoices or promised performance is ordinary contract liability, not a management wrongful act, and contractual-liability wording can keep the amount owed out of covered loss.

It gets closer when the complaint also accuses your directors or officers of misleading conduct. Then compare the complaint with the policy's wrongful-act definition, the contract exclusion and its exceptions, and any professional-services exclusion. Individual cover (Sides A and B) applies only to an insured person sued for covered conduct; entity cover (Side C) applies only if the company is insured for that type of claim.

If the counterparty is an investor or affiliate, check the insured-versus-insured exclusion. If the dispute is about services you delivered to a customer, errors and omissions (E&O) insurance is the policy to look at.