@redi = $responsetextall[$i][$j]{set}{Client}{redirect_uris};
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The right hand side of the assignment is a value from a deeply nested hash. The value of a hash is always a scalar, i.e. a single value.

Show us the code where you populate the inner hash. You might need to use an anonymous array as the value:

$responsetextall[$i][$j]{set}{Client}{redirect_uris} = [
    'http://abcd01.cpu.comp.com:80/AutosysPortal/',
    'http://abcd01.cpu.comp.com:80/Da/',
    'http://abcd01.cpu.comp.com:80/Ge/',
    'http://abcd01.cpu.comp.com:80/PO/',
    'http://abcd01.cpu.comp.com:80/g/' ];
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and then you need to dereference the value:

@redi = @{ $responsetextall[$i][$j]{set}{Client}{redirect_uris} };
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or (requires 5.20)

@redi = $responsetextall[$i][$j]{set}{Client}{redirect_uris}->@*;
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