You can wait for an answer here, maybe someone will be able to help you. But please understand that this is the InfinityFree forum. We’re experts on our hosting, but not experts of all software imaginable you could run on it.
The question you have is extremely specific to MyBB, and you’ll probably need a MyBB expert to answer it. Maybe you can find someone here, but you will probably have a lot more success if you go to the place where you’re more likely to find people with the knowledge you need.