PowerShell remoting from trusted domain server to trusting domain server

Hi all, I have one way trust between forest A and forest B (forest B trusts forest A). Having set up WinRM on source server in forest A/target server in forest B I added my domain admin account from forest A to be local admin on target server in forest B. Now I can connect from source server in forest A to target server in forest B by using Windows PowerShell remoting but only if I enter my domain admin username/password from forest A - if I omit credentials (I am already logged in elevated PowerShell console as domain admin from forest A) connection fails as if my domain admin credentials can not be passed to target server in forest B.

To ilustrate, this works:

PS C:> Enter-PSSession -ComputerName targetServerFQDN -Credential (Get-Credential)

cmdlet Get-Credential at command pipeline position 1
Supply values for the following parameters:
Credential
[targetServerFQDN]: PS C:\Users\BojanZAdm.FORESTANETBIOSNAME\Documents>

This does not work:

PS C:> Enter-PSSession -ComputerName targetServerFQDN
Enter-PSSession : Connecting to remote server targetServerFQDN failed with the following error message : WinRM cannot process the request. The following error occurred while using Kerberos authentication: Cannot
find the computer targetServerFQDN. Verify that the computer exists on the network and that the name provided is spelled correctly. For more information, see the about_Remote_Troubleshooting Help topic.
At line:1 char:1
+ Enter-PSSession -ComputerName targetServerFQDN
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (targetServerFQDN:String) [Enter-PSSession], PSRemotingTransportException
+ FullyQualifiedErrorId : CreateRemoteRunspaceFailed

PS C:> whoami
FORESTANETBIOSNAME\bojanzadm

How to solve this? Thanks in advance!!!