I am having trouble accessing a shared network location while within a PowerShell remote session.
From the PowerShell prompt, I enter a new session:
Read the section "Credential Delegation" Here - Credit to Keith Hill and perform the steps if you have not already done so.
If you can't use credential delegation as mentioned above, you can mount (or just authenticate as below) the remote share in the remote session using explicit credentials, e.g.
[server1] ps> net use \\server2\share * /user:username
(prompts for password)
[server1] ps> dir \\server2\share
(listing)
This problem has nothing to do with powershell per-se; you are trying to replay your local credentials in a remote session to a third location and falling foul of the NTLM "double hop" limitation.