You may face Unexpected (T_LNUMBER), expecting identifier (T_STRING) system error when you are trying to get value of JSON variable and that variable key contain any number.
For example when you are trying to write code something like this $result->response->3d_secure
Here is you can see 3 is there in the JSON variable so when you write code like this you will get this error message and this is syntax error message nothing else.
Solution of Unexpected (T_LNUMBER), expecting identifier (T_STRING) system error:
Write code like this
$result->response->{‘3d_secure‘}
Instead of this
$result->response->3d_secure
Conclusion: If JSON contains digits then just write that variable between {‘ ‘} to solve this issue.