Ford Fiesta 1.1 sometimes doesn’t start

Hello, I have a Ford Fiesta 1.1. Year of construction 1995. He sometimes doesn’t start. Sometimes he does not start for 4 days then again and sometimes he starts a day and then he doesn’t. If he then jumped in the morning sometimes after 10 times try or push then he starts the whole day without any problems.As I said, that’s just not every day so that he doesn’t start and that’s always only in the morning (so at the first start in the early)! ? Battery and spark plugs are new and other things like Zb: brake fluid etc but they have nothing to do with it. Would be nice if you could help with it. Thank you in advance Lysarent