Request Body should be a valid JSON object. (300)

[dompl]

Hi.

First of all, thank you very much for your work on this. Absolutely amazing!

I do indeed have an issues I cant resolve.

The response returns with

[body] => <?xml version="1.0" encoding="UTF-8" standalone="yes"?><error><code>300</code><message>Request Body should be a valid JSON object.</message></error> [response] => Array ( [code] => 400 [message] => Bad Request )

Would you know what could cause it?

Thank you in advance!