Problem is network related. OBS is losing connection to the YouTube ingest server. Regular intervals suggests connection throttling, either by a local router or your ISP.
19:18:39.752: WriteN, RTMP send error 32 (4097 bytes)
19:18:39.752: WriteN, RTMP send error 32 (54 bytes)
19:18:39.753: WriteN, RTMP send error 9 (42 bytes)
19:18:39.753: [rtmp stream: 'simple_stream'] Disconnected from rtmp://b.rtmp.youtube.com/live2?backup=1
19:18:39.753: Output 'simple_stream': stopping
19:18:39.753: Output 'simple_stream': Total frames output: 62966 (63511 attempted)
19:18:39.753: Output 'simple_stream': Total drawn frames: 63527 (63557 attempted)
19:18:39.753: Output 'simple_stream': Number of lagged frames due to rendering lag/stalls: 30 (0.0%)
19:18:39.753: Output 'simple_stream': Number of dropped frames due to insufficient bandwidth/connection stalls: 545 (0.9%)
19:18:39.753: Output 'simple_stream': Reconnecting in 1 seconds..
19:18:39.753: [rtmp stream: 'simple_stream'] Freeing 787 remaining packets