Two studio issues i am having

Hello

I have been running into two issues.
First one is that when i do a very simple world tracking, just adding the world tracking symbol and adding a 3d images, when i go to preview sometimes it works, sometimes it doesn’t even though i am doing the same thing over and over again

2nd one is that when i try to import a 3d file from sketchpad it does not let me login to sketchpad it either says password is incorrect or i may be using the wrong browser

any help