So, can you please check what the value of rc is when the problem occurs. It may be that the connection is being closed by the peer when the SSL engine is not expecting it (or possibly a bug in openssl_operation that means it erroneously reports EOF to the SSL engine).

When the error occurs, here's the values I'm seeing going from top to bottom: int rc = primitive_( session_ ); // -1 int sys_error_code = (int)ERR_get_error(); // 0 bool is_operation_done = (rc > 0); // false int error_code = !is_operation_done ? // 5 bool is_read_needed = (error_code == SSL_ERROR_WANT_READ); // false bool is_write_needed = (error_code == SSL_ERROR_WANT_WRITE || // false bool is_shut_down_received = // false bool is_shut_down_sent = // false HTH, Scott