Posting new bill fails with "Invalid JSON"

Hi there,
I’m trying to POST the following new bill through the API and receive the error “Invalid JSON” from the server:
{
“bill” : {
“category” : “https://api.freeagent.com/v2/categories/200”,
“contact” : “https://api.freeagent.com/v2/contacts/5262821”,
“dated_on” : “2019-09-02”,
“due_on” : “2019-09-02”,
“reference” : “2019-09-02”,
“sales_tax_rate” : “0”,
“total_value” : “87”
}
}

I can’t for the life of me find anything wrong with it…?

Any help would be much appreciated!

Alex

Ok, found the problem. The Google API client library (java) sends content gzipped by default. Disabling this makes everything work!