Having issues with the Next/Back button

Hello there,

First time writing here. First E-Learning course in Storyline. And please note that my English is my second language (I'm French Canadian)!

I am having problems with my Next & Back buttons and this is not a constant situation. Sometimes, my buttons are working properly as other time, the triggers does not work. This is a situation is very irritating due to the non-consistency of these actions. Does this happened to any of you and, is there a way to fix that problem ?

Navigation buttons all have specific triggers such as being disabled at the beginning of the slide; then, being normal state when something happen; and finally, go to the next slide when clicking on the next button.

Note that due to confidential aspect, I can not upload my course online (maybe in a private way though).

Thank you in advance for your help!