I can't open PDF through F5 LTM/ASM

Hi Hamza , 
Try to disable ASM policy first from your Virtual server and see if this fixed this issue or not ,

-if yes you should see what makes ASM to block opening or downloading PDF files requests ,

-If not you should disable http profile from your virtual server and change virtual server type from standard to performance layer 4 " If this available with you and this web site does not serve production services now " , if this issue resolved , I recommend to disable http parsing against PDF files as clarified in the below KB : 

https://support.f5.com/csp/article/K00445006

but first differentiate if this an ASM issue or not. 

I hope this helps you

Hi

in my case

abnomal http protocol.

if you can check the content length, Because Web Firewall solutions view content sizes, signatures are detected when data sizes are different.