After some time I opened my unity project and suddenly some of the text in my buttons shifted. I did not change the settings in my Canvas, in fact I have not changed any code recently relating to UI. Also sometimes I open my project and the text is blurry. Some days the text is very clear. Whats going on?
I suggest in the game view you select an aspect ratio that looks closet to the screen size you are targeting. Then in the Canvas Scaler properties select Pixel Perfect then set it to scale with screen size. In the Text component for the Login button set its size to fill parent width and height (Top 0, Bottom 0, Left 0, Right 0) and set the vertical alignment of the text center. Also its good to use the Best Fit property on the text and then set the values for the minimum and maximum text sizes that makes your text look good and still be readable.