Rasa mode/train api giving 500 response

Hello

I am trying to train the model using rasa’s model/train api passing yaml data content-type = application/x-yaml body - raw text

in response getting 500 intental server error

error states - an unexpected error occurred during training, failed to read ‘tmp/tmptssmd0ze/data.yml’, mapping values are not allowed here’

could anyone help please

Thank you