Yes—this is mainly a focusing issue. In very low light, autofocus may fail because it needs enough light and contrast.

Try these options:

• use manual focus when autofocus can’t lock. You may need a little trial and error, but it’s often the most reliable method in the dark.
• use live view to help with manual focus, if the screen is bright enough to see the subject.
• if you’re using a flash unit, check whether it has an AF-assist beam. This projects a pattern that helps the camera focus in low light.
• on Canon, the flash AF-assist typically works only in one shot AF mode, not AI Servo.
• use a creative mode such as av, tv, or m so you can control focus settings; some fully automatic modes may limit those options.

Also remember that AF-assist has limited range, so if the bat is too far away it may still not help. In that case, manual focus is your best bet.