Here are some points to keep in mind when creating a domain trust.
Before the Local Security Authority (LSA) creates the trust, the LSA verifies the consistency of the following parameters:
1. The NetBIOS name of the domain
2. The fully qualified domain name (FQDN) of the domain
3. The security identifier (SID) of the domain
The above items must be unique in-order to successfully establish the Domain Trust. So if you have any duplicate or conflicting names, you won’t be able to establish the domain trust.