Zoom rejects creation of meeting: 300Request Body should be a valid JSON object.

Zoom API calls log:

{
"endpoint": "https://api.zoom.us/v2/users/me/meetings",
"response_headers": [
"Set-Cookie: zm_aid=""; Domain=.zoom.us; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; Secure; HttpOnly"
],
"date_time": "2020-09-10 14:17:36",
"method": "POST",
"request_body": "{"topic":"Test","type":2,"start_time":"2020-09-10T17:00:00Z","duration":30,"agenda":"Moreinformationathttps:\/\/itiscotland.org.uk\/events\/test\/","settings":{"approval_type":"1","contact_name":"xxxxx","contact_email":"[email protected]","registrants_confirmation_email":true,"registrants_email_notification":true,"host_video":true,"password":"xxxxxxxx-x","participant_video":true,"join_before_host":false,"mute_upon_entry":false,"watermark":false,"use_pmi":false,"audio":"both","auto_recording":"cloud","alternative_hosts":"","close_registration":true,"waiting_room":true,"meeting_authentication":false,"authentication_domains":"","allow_multiple_devices":false,"global_dial_in_countries":"GB","registration_type":2},"timezone":"Europe\/London"}",
"response": "<?xml version="1.0" encoding="UTF-8" standalone="yes"?><error><code>300</code><message>Request Body should be a valid JSON object.</message></error>",
"request_headers": [
"accept-encoding: deflate, gzip",
"accept: */*",
"authorization: ******",
"connection: close",
"content-type: application/json",
"user-agent: WordPress/5.5.1; https://itiscotland.org.uk"
],
"request_params": [
],
"http_status": "400"
}