The error is saying that SAS Studio is trying to access some path within the compute server, and that path is inaccessible.
From the supplied information it is unclear what path is inaccessible. The compute server pod log will probably have that information, or a network trace (HAR file) from the browser when reproducing the failure.
My guess would be something to do with the configured file navigation path for SAS Studio since it's happening as soon as you try to start using SAS Studio, which I think by default is the user's home directory. If this is being mounted in and is owned by a different UID/GID than what is being assigned through Viya, the user might not have access.
A SAS Technical Support case would probably be the fastest path to resolution here.
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Greg Wootton | Principal Systems Technical Support Engineer