If we take this at face value, the reason why you get fired is clear: Your performance is significantly lower than what the employer expects. The only real solution here is to improve your performance, or find employers with lesser expectation. I won't go into detail about *how* to accomplish these things because those would be separate questions (and probably asked already on here in many variations).

What is strange to me is how quickly you've been fired. Assuming you've had a typical interview process that takes 2-3 weeks, any major flaws you have would be apparent to the employer and they wouldn't hire you in the first place. If you had an obvious, major flaw they discovered after 2 weeks as in job 1, why didn't they discover it during interviews? That leaves me to conclude that one of the following is true:

* You are really, really good at interviewing. If so please tell the rest of us your secret, but also, don't take the highest job you can get. Go for something easier.
* Your employers are really, really bad at interviewing. Now occasionally you get a company that doesn't know how to interview but it's here and there. You wouldn't get a string of 5 just by chance. That means something about what *you're* doing is selecting for companies that are totally rubbish at interviewing. Maybe it's just how your resume and cover letter is written, or maybe it's just which ones you decide to apply for.
* It's not performance, it's something else, and performance is used as cover. For example, if you piss off the CEO on your first day, you would probably be fired, but they're not going to say it was because you annoyed the CEO. They'll say some generic reason like "poor performance". But in your case, whatever this something else is, it's something consistent enough that you've done it 5 times in a row.

To summarize, what you said makes no sense. Firing people months or weeks (!!!) after they started is not good, it costs the company a lot of money. It wastes all the time and effort spent on hiring you, training you. It makes the guy who hired you look bad, makes the guy who fired you look bad, makes the guy who managed you look bad, disrupts the work of people already working there... And in such a short time they don't get any useful work out of you to offset these things. So people don't get fired that soon merely for poor performance, they get fired for catastrophically bad performance. And the whole point of interviewing is to eliminate candidates who will perform so poorly they will need to be fired right away. As a result, you should carefully review the situation to see what critical points you are overlooking.