In principle, a business closure is a permissible reason for dismissal for operational reasons, as the closure of a business is an "urgent operational requirement". Nevertheless, these dismissals are often legally contestable. You should therefore not accept them without further ado, as there may be a chance of longer pay, a higher severance payment or keeping your job.
If your business is only being closed temporarily, is being sold, is still in the planning phase or is being closed in several stages, you have a realistic chance of successfully taking legal action against the dismissal. Employers often dismiss employees too early, even if the dismissal is justified for operational reasons. With the help of a lawyer specializing in employment law, you can achieve the payment of further salaries or longer employment with the company.