Incorrect sending format OCR for capmonster

[m1stdev]

[Executing block Solve Image Captcha] TaskSolutionException: Buffer_cannot_be_null.

Solution is here

POST /in.php HTTP/1.1
Host: MYHOST
User-Agent: IPWorks HTTP Component - www.nsoftware.com
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
Content-Length: 9371

key=123456&method=base64&body=<URLENCODEBASEIMG>&regsense=1&min_len=5&max_len=5

Where URLENCODEBASEIMG is url encoded base64 image