Cannot create trigger personalization trail Can't unmarshall error

I'm on the part "Creating a new trigger" on the trail "Personalization Trail" under:

 https://help.hybris.com/6.7.0/hcd/d493b645afb74c439a15fc6fbc78c8f9.html#copyd493b645afb74c439a15fc6fbc78c8f9

When trying to create a new trigger without userGroupUid to verify that the validator works with the the following command as in the trail:

 curl --insecure --verbose --header "Authorization: Bearer cd12848b-5f21-433a-a33c-9d91753b647e" --header "Content-Type: application/json" https://localhost:9002/personalizationwebservices/v1/catalogs/electronicsContentCatalog/catalogVersions/Staged/customizations/Banner/variations/variationForUserGroup/triggers --request POST --data '{"type" : "userGroupTriggerData","code" : "newUserGroupTrigger"}'

I got the following error and don't know how to fix it. Does anyone have an idea? Thanks!:

 *  issuer: C=DE; ST=yDevelopers; L=yDevelopers; CN=yDevelopers
 *  SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
 > POST /personalizationwebservices/v1/catalogs/electronicsContentCatalog/catalogVersions/Staged/customizations/Banner/variations/variationForUserGroup/triggers HTTP/1.1
 > Host: localhost:9002
 > User-Agent: curl/7.61.1
 > Accept: */*
 > Authorization: Bearer cd12848b-5f21-433a-a33c-9d91753b647e
 > Content-Type: application/json
 > Content-Length: 6
 >
 * upload completely sent off: 6 out of 6 bytes
 < HTTP/1.1 400
 < X-Frame-Options: SAMEORIGIN
 < Cache-Control: no-cache, no-store, max-age=0, must-revalidate
 < Pragma: no-cache
 < Expires: 0
 < Strict-Transport-Security: max-age=16070400 ; includeSubDomains
 < X-XSS-Protection: 1; mode=block
 < X-Content-Type-Options: nosniff
 < Content-Type: application/json;charset=UTF-8
 < Transfer-Encoding: chunked
 < Date: Fri, 18 Jan 2019 08:08:49 GMT
 < Connection: close
 <
 {
    "errors" : [ {
       "message" : "Can't unmarshall input to class: class de.hybris.platform.personalizationfacades.data.TriggerData",
       "type" : "HttpMessageNotReadableError"
    } ]
 }* Closing connection 0
 * TLSv1.2 (OUT), TLS alert, close notify (256):
 Note: Unnecessary use of -X or --request, POST is already inferred.
 * Bad URL, colon is first character
 * Closing connection -1
 curl: (3) Bad URL, colon is first character
 Note: Unnecessary use of -X or --request, POST is already inferred.
 * Rebuilt URL to: userGroupTriggerData,code/
 * Could not resolve host: userGroupTriggerData,code
 * Closing connection 1
 curl: (6) Could not resolve host: userGroupTriggerData,code
 Note: Unnecessary use of -X or --request, POST is already inferred.
 * Bad URL, colon is first character
 * Closing connection -1
 curl: (3) Bad URL, colon is first character
 curl: (3) [globbing] unmatched close brace/bracket in column 20