Raspberry pi not booting

[zephir...@gmail.com]

Hello,

I have installed kivy pi on my SD Card, however, when I insert it in my raspberry pi and turn it on, I only get the rainbow screen with the lightning logo at the top right. Also, the rapsberry pi power red light blinks rapidly then slowly, then rapidly, then slowly... check this video I uploaded : https://drive.google.com/file/d/1kXTa_j4lk8uzF0CL_9GOUXKwB_TFDQZB/view?usp=sharing

I tried booting it with Raspbian Stretch and it worked but when I tried to install Kivy on it it did not work, that's why I tried kivypi, without success.

Can anyone help please?

Thanks!

[zephir...@gmail.com]

Btw, I have a raspberry pi 3b+ and tried two different power source