Hello,
The errors you’re seeing point to a breakdown in how the RD Connection Broker and Session Hosts are resolving security identifiers across the forest trust. Even though the trust is two‑way, RDS relies heavily on proper DNS resolution, RPC/LDAP connectivity, and SID translation between domain controllers. Let’s address each of your issues in context.
For the “security identifier could not be resolved” and “network path was not found” errors, the most common cause is DNS misconfiguration. The Connection Broker must be able to resolve the fully qualified domain names of the trusted domain controllers. Verify that conditional forwarders or stub zones exist for each domain in the opposite forest, and confirm that nslookup against the trusted domain controllers works from RDS1. Also ensure that the firewall allows RPC (TCP 135), LDAP (TCP/UDP 389), Kerberos (TCP/UDP 88), and the ephemeral RPC range (TCP 49152–65535 by default). If any of these are blocked, SID resolution will fail with exactly the error you’re seeing.
The “username or password is incorrect” error when browsing objects is misleading. It usually indicates that the RDS server is unable to contact a domain controller in the trusted domain to validate the credentials. Run nltest /dsgetdc:<TrustedDomain> from RDS1 and RDS2 to confirm that a domain controller is being located. If this fails, it’s either DNS or firewall. Also check that the RDS servers are not restricted by the “Deny logon locally” or “Deny logon through Remote Desktop Services” policies for the trusted domain accounts.
Regarding the RemoteApp disconnection error (0x300000d), yes, this is often a downstream effect of the Connection Broker not being able to resolve and authorize the user’s SID from the trusted domain. If the Broker cannot enumerate the user or group membership, it cannot issue the proper RDP file or feed, and the client will fail with that error. Once SID resolution is fixed, the RemoteApp launch issue should clear.
To validate that the Connection Broker can query the trusted domain, use wbemtest or ldp.exe from RDS1 to bind against a domain controller in the trusted domain using a trusted domain account. If the bind fails, you know it’s a connectivity or authentication issue. Also, check the Broker logs under Applications and Services Logs > Microsoft > Windows > TerminalServices-SessionBroker for Event IDs 1296 and 1297, which will show domain resolution failures.
In short, the next checks should be: confirm DNS forwarders/stub zones, verify Kerberos and LDAP ports are open between forests, run nltest to ensure domain controllers are discoverable, and test LDAP binds manually. Once those succeed, adding trusted domain users/groups should work, and RemoteApp publishing will function correctly.
I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!
HP.