Getting when when trying to extract value from post request response body using json

Hi I am new to gatling and performance testing and I am stuck at one place. I am trying to extract sessionID from post request response body and this is getting failed. Below is my cod and result. When I validated json path, it is giving me correct value. Why Gatling is not outputting me value

.check( jsonPath( "$" ).saveAs( "RESPONSE_DATA" ) )

 //.check( jsonPath("$..[11].contextValue").saveAs("SessionID")))
  .check( jsonPath("$.[11].contextValue").saveAs("ID")))
.exec( session => {
 println( "TeamXP Login Response Body:" )
 println( session( "RESPONSE_DATA" ).as[String].contains("pcwxSessionID") )
 println(session ("Response_Body").as[String])
 println(session ("ID"))

I am getting below output

---- Errors --------------------------------------------------------------------

jsonPath($.[11].contextValue).find.exists extraction crashed: 1 (100.0%)
string matching regex ‘[^*.()=!<>\s]+’ expected but '[…

Because the online evaluator you used is completely buggy.
It’s based on a given js implementation and someone build an online version and purchased the domain domain name.
By no means does it make it a reference implementation.

[number] is an operator, so having is preceded by a dot is incorrect syntax.
Moreover, it works on arrays, where do you have one?