EOS 4000D display not working and error messages

[JJ_pictures]

Make: Canon

Model: EOS 4000D 18-55mm Lens

DS126701  ;  6730[XXXXXXXX] 

• I just tried to turn my camera on to take headshots and #1) the display did not turn on but #2) the viewfinder displayed information, and most recently I recieved a "busy" message when taking out the battery as well as the SD card, and followed up shortly after with a flashing "Err" (for error). 
• I have not had prior issues with this camera. 
• I do not have a battery replacement to test if its the camera or the battery but prior to this the battery was working just fine and it is fully charged. 
• While the main display used to work with no issues, for some reason whatever charge or life there is seems to go to the viewfinder to tell me there's an issue, and then the camera no longer functions at all after that. 
• The red dot does come on when the battery is first inserted, at least temporarily. (don't know what this means...) 

Any help would be greatly appreciated. My only thoughts at this point are to swap out the battery, because I don't think a simple SD card issue would cause the main display to be all black. 

[Serial number partially hidden to protect privacy.]

[deebatman316 · Accepted solution]

What error code is the camera displaying. We need to know the exact error code. Cameras can report multiple error codes so we need the exact code. Or we’re guessing at what’s wrong. What kind of SD Card is it. Is it a Full Sized SD Card or a Micro SD Card in an adapter. Adapted Micro SD Cards do not work reliably and cause problems. Stick with a full sized SD Card. What size is it capacity wise ie 32GB for example. That particular lineup of cameras is known not to work well with SD Cards larger than 32GB. Even though the manual says it’s “compatible” it’s not. It will cause the camera to lock up and freeze. Are you using an accessories on your camera such as an external flash or battery grip.