Recipient Not Found By Exchange Legacy Encapsulated Email Address Lookup. Within outlook there is configured for both the exchage enviroments an account. So take a look at this the legacyexchangedn should be extracted and turned into an x500 and inserted in the proxy addresses field.
Recipient not found by exchange legacy encapsulated email address lookup'. Recipient not found by exchange leg we have user that has in two different hybrid exchange environments an account. Remote server returned '550 5.1.10 resolver.adr.recipientnotfound;