EDIT: seem that 1714 bytes like packet lenght (default) are the problem.
if i set 1650 or less no problem :/
Thank you, changing the packet length was one of the other suggestions I was going to make :)
As you say 1714 is the default and will have been used in all our testing so I don't know why it would cause you a problem. The max MTU for ethernet is 1500 I think, so unlikely to cause you any problems if you are OK with 1650.
This (MTU, frame sizes, etc) isn't my area of expertise but I will raise this in our bug tracking system and see if anyone else has any ideas.
best regards
Andy.