Canon EOS Rebel SL2 EOS 200D Instruction Manual page 415

The image is out of focus or blurred.
Set the lens's focus mode switch to <AF> (p.48).
Press the shutter button gently to prevent camera shake (p.50-51).
With a lens equipped with the Image Stabilizer, set the IS switch to
<1>.
In low light, the shutter speed may become slow. Use a faster shutter
speed (p.164), set a higher ISO speed (p.132), use flash (p.182), or
use a tripod.
I cannot lock the focus and recompose the shot.
Set the AF operation to One-Shot AF. Focus lock is not possible in the
AI Servo AF mode or when servo takes effect in AI Focus AF mode
(p.114).
Horizontal stripes appear, or the exposure or color tone
look strange.
Horizontal stripes (noise) or irregular exposures can be caused by
fluorescent lighting, LED lighting, or other light sources during
viewfinder or Live View shooting. Also, the exposure or color tone may
not come out right. A slow shutter speed may reduce the problem.
Troubleshooting Guide
415