HACKED!!!
Dec 30 09:05:20 SERVER nginx: 2020/12/30 09:05:20 [error] 8506#8506: *8967102 FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream, client: 178.128.163.10, server: , request: "GET /system_api.php HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "107.179.228.5:8006"
...
Jan 20 07:26:44 SERVER nginx: 2021/01/20 07:26:44 [error] 8506#8506: *12742830 open() "/usr/local/emhttp/c/version.js" failed (2: No such file or directory), client: 167.99.241.151, server: , request: "GET /c/version.js HTTP/1.1", host: "107.179.228.5:8006"
...
Jan 27 12:34:37 SERVER nginx: 2021/01/27 12:34:37 [error] 8506#8506: *13851431 FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream, client: 64.227.97.101, server: , request: "GET /system_api.php HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "107.179.228.5:8006"
...
https://www.abuseipdb.com/check/178.128.163.10 UK
https://www.abuseipdb.com/check/167.99.241.151 Germany
https://www.abuseipdb.com/check/64.227.97.101 USA
Also looks like you have a problem with cache disk.
Feb 4 09:03:08 SERVER kernel: sd 1:0:5:0: [sdg] tag#537 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=0x08
Feb 4 09:03:08 SERVER kernel: sd 1:0:5:0: [sdg] tag#537 Sense Key : 0x5 [current]
Feb 4 09:03:08 SERVER kernel: sd 1:0:5:0: [sdg] tag#537 ASC=0x21 ASCQ=0x0
Feb 4 09:03:08 SERVER kernel: sd 1:0:5:0: [sdg] tag#537 CDB: opcode=0x42 42 00 00 00 00 00 00 00 18 00
Feb 4 09:03:08 SERVER kernel: print_req_error: critical target error, dev sdg, sector 1953277894
Feb 4 09:03:08 SERVER kernel: BTRFS warning (device sdg1): failed to trim 1 device(s), last error -121