I also agree with ZS and see if there is any clues he can give you. In our case it was really challenging to get to the bottom of the problem. His behavior at school was completely different than at home and it was like we were dealing with two different kids. In the end for us an LD diagnosis made a lot of sense for him. At home he was focusing on the things he was naturally good at and was free to explore his obsessions and we were able to see his intelligence. At school however he was forced to do things outside that bubble (and in such a way that he wasn't able to compensate with the gifted side) and then the issues dominated and you'd have a hard time seeing anything remotely gifted about him. On top of that, add on him feeling like he was "dumb" and he did everything he could to hide it or distract from it. When we told him the basics of the test results you could almost see the relief wash over him that there was an explanation (other than "being dumb") for what he was going through and that it didn't mean he wasn't smart after all.
Anyway, definitely explore all possibilities and see what the school has to say but if you can't get any answers I'd suggest testing him and see if someone with 2e experience can make any sense of it. There are a LOT of different types of LDs and most teachers aren't trained to recognize or deal with them. Prior to this DH and I had only ever heard of dyslexia and that's where our LD knowledge stopped. Going in I would have never guessed an LD but once the results were explained it made a lot of things clearer. I just always thought he was a selective listener or that he was stubborn or that he just didn't like to do "x", or....
I'm sure there are lots of other possibilities and I'm obviously skewed based on my experience so that's what I default to. Whatever it is, hopefully you can get to the bottom of it sooner than later. It is not a fun place to be.
