My Exchange Server was working as a DC but i had many problems with this configuration. For solving these problems i decided to remove the DC configuration over Exchange Server using dcpromo command.
When Exchange Server was DC secondary, RPC Over HTTP service was working fine, but now not because i have problems with trust certificates. I can use RPC Over HTTP and OWA from internal network but i can't use RPC Over HTTP from External Network because i receive a certificate error.
I hope that you can help me.