strace will give you the same message

setuid32(0) = -1 EPERM (Operation not permitted)
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Not that helpful, except it tells you which system call's man page you should be reading.

$ man setuid32
...
       EPERM  The user is not privileged (Linux: does
              not have the CAP_SETUID capability) and
              uid does not match the real UID or saved
              set-user-ID of the calling process.
...
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