JSON decode extra character error

I have tried using both of these scripts to decode json files into matlab structures.

filename='sample.json';
str=fileread(filename);
JSONstruc=jsondecode(str);

filename='sample.json';
fid=fopen(filename);
raw=fread(fid,inf);
str=char(raw');
fclose(fid);
JSONstruc=jsondecode(str);

Both versions work fine for one sample json file but I get the same error for a second json file

Error using jsondecode

JSON syntax error at line 2,column 1(character ____):extra text

I'm using Matlab R2023b.

[Sandeep Mishra]

Hi @Paulo

Is the error occurring in just one specific file? If so, there might be an issue with that JSON file. Could you please share it for better analysis?