I have sharepoint running with ltm and asm, but I have faced many rejected requests with different violations. Mostly, attack signatures, illegal parameters, and illegal urls. The setup is normal with no iApp . So, is there any iApp for SharePoint? Will iApp fix this issue?
ASM (AWAF) should not be set up with everything on and in blocking. That's not how it works. With ASM, you want to develop a policy before putting it in blocking mode, if you can. The easiest way to do that is to develop a policy "in QA,' by sending ONLY good traffic at the VIP with the policy. Once you've sent a QA run at it, AWAF can learn all as good / expected traffic. At that point, you can put the policy in blocking mode on your production VIP.
The trickiest bit with Sharepoint is the dynamic URIs. I think there may be a pre-built policy for Sharepoint, if I'm not mistaken. What version are you on?