in reply to Modification of a read-only value attempted

>   my $respons = $response[$i][$j]{creden}{uName};

That's supposed to be the line causing this error?

No way...

Help us to help you by providing more insight.

update

the only possibility I see is auto-vivification of non existent entry "creden" provided $response[$i][$j] is read-only. (if that's even possible)

A prior check would solve this!

update

though the error messages don't match. 

  DB<72> $a{1}=\1

  DB<73> use warnings; say $a{1}{foo}{bar}
Not a HASH reference at (eval 81)[c:/Perl_524/lib/perl5db.pl:737] line
+ 2.

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Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

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Re^2: Modification of a read-only value attempted (Readonly + autovivification)
by LanX (Saint) on Feb 01, 2021 at 14:58 UTC
    So I was able to reproduce it 
      DB<75> use Readonly;

  DB<77> Readonly::Hash    %has => (key1 => 1, key2 => 2 );

  DB<78> x \%has
0  HASH(0x332b388)
   'key1' => 1
   'key2' => 2
  DB<79> $a{1}=\%has

  DB<80> use warnings; say $a{1}{foo}{bar}
Modification of a read-only value attempted at (eval 94)[c:/Perl_524/l
+ib/perl5db.pl:737] line 2.

  DB<81>

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    you must check if there is any key {creden} before trying to access a deeper key.

    no autovivification is another possibility.

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery

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Re^2: Modification of a read-only value attempted
by chandantul (Scribe) on Feb 01, 2021 at 15:14 UTC

    This is the JSON response, i suppose to capture below for all 1000 users

      "creden": {
        "uName": "5xxxxxxx"
    },

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