[j-nsp] MTU problem

[S B]

Hi all,

site A -----  PE1--- MPLS cloud ---- PE2 --- site B

There is a SAP server on site B.The users on site A  could not login
SAP server.However they can reach every server on Site B and they
could use SiteB's internet connection.There is no any filter on the PE
routers.I think this is a mtu problem .The mtu of ldp running
interfaces is 1488 btye.I increase it 1500.But it did not solve my
problem.Have you got any idea about the problem?

Best Regards.

Ps:There are cisco routers and cisco switches on site a and site b.The
pe routers are juniper.