c# image upload to service issue with f5 firewall

i recently faced an issue with a firewall called f5, the issue began when i upload image, check the attached image.

the firewall blocks the stream of bytes.

so i dont know if the problem is in my code or in the firewall.

to be sure that my code have no problem i made and mvc application to test upload and in fiddler the same symbols appeared

fiddler capture for mvc upload.

Firewall Error Image