Hello @Sky2 and welcome to the forum 
Which version of krita are you using and which Linux distribution?
Please note that there is currently a problem with the flatpack for krita and this is discussed here:
Krita Flatpack crashes when opening a file dialogue
It would be a good idea to use the appimage which is the official way of running krita on Linux and is available here so please try that. (Remember to give it execution permissions.):
Download | Krita
Please upload a full screen screenshot of your animation with the Animation Timeline docker and the Layers docker and the canvas fully visible.