What is your OBIEE version 10g/11g/12c?
Found below document related to OBIEE 10g for similar issues discussed in the document:
OBIEE 10g: Error:" [nQSError: 77006] Unexpected end of file encountered. 4 bytes were requested and 0 bytes were read. Error Codes: KUWODMKH" while sending iBots. (Doc ID 1498021.1)
OBIEE 10g: iBot fails with 'Unexpected end of file encountered. 4 bytes were requested and 0 bytes were read' error in SSO-Enabled Environment (Doc ID 1285864.1)
I'm using OBIEE 11g(1.1.7)