Input/output error on USB disks when I use qBittorrent

I'm using Ubuntu 20.04 on a Raspberry Pi 4. I connected 4 USB disks to the Pi: two USB 2.0 disks to USB 2.0 ports and two USB 3.0 disks to a USB 3.0 hub connected to one of two USB 3.0 ports. All disks have ext4 partitions only and they are mounted via /etc/fstab, some of them are shared via Samba. Normally everything works like a charm for hours but if I run qBittorent (and aMule too...) after few minutes I can't access to some partitions on these disks, if I do ls -l in directories where partitions are mounted I get ls: reading directory '.': Input/output error. This happens on four partitions on three disk, another partition on the fourth has no problems... A sudo dmesg | tail -n 100 reveals:

[64119.839763] sd 3:0:0:0: rejecting I/O to offline device
[64119.846414] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64119.848772] sd 3:0:0:0: rejecting I/O to offline device
[64119.860948] sd 3:0:0:0: rejecting I/O to offline device
[64119.867406] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64119.873906] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64119.897286] EXT4-fs (sdd1): I/O error while writing superblock
[64119.897288] EXT4-fs (sdd1): previous I/O error to superblock detected
[64119.897329] sd 3:0:0:0: rejecting I/O to offline device
[64119.919401] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64119.928595] EXT4-fs (sdd1): I/O error while writing superblock
[64119.936127] sd 3:0:0:0: rejecting I/O to offline device
[64119.942724] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64119.956978] sd 3:0:0:0: rejecting I/O to offline device
[64119.963560] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64119.972751] EXT4-fs (sdd1): I/O error while writing superblock
[64119.980240] sd 3:0:0:0: rejecting I/O to offline device
[64119.986824] print_req_error: 13 callbacks suppressed
[64119.986828] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64120.000437] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64120.014729] sd 3:0:0:0: rejecting I/O to offline device
[64120.021313] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64120.034341] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64120.047350] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64120.056545] EXT4-fs (sdd1): I/O error while writing superblock
[64120.081463] sd 3:0:0:0: rejecting I/O to offline device
[64120.088063] blk_update_request: I/O error, dev sdd, sector 923011280 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[64120.101377] sd 3:0:0:0: rejecting I/O to offline device
[64120.107971] blk_update_request: I/O error, dev sdd, sector 923011280 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[64120.545599] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64125.665708] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64126.112217] sd 3:0:0:0: rejecting I/O to offline device
[64126.118827] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64126.132425] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64126.146698] sd 3:0:0:0: rejecting I/O to offline device
[64126.153301] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64126.166327] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64126.179334] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64126.188533] EXT4-fs (sdd1): I/O error while writing superblock
[64126.196095] sd 3:0:0:0: rejecting I/O to offline device
[64126.202688] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64126.216286] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64126.230554] sd 3:0:0:0: rejecting I/O to offline device
[64126.237138] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64126.250158] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64126.263163] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64126.272355] EXT4-fs (sdd1): I/O error while writing superblock
[64126.304611] sd 3:0:0:0: rejecting I/O to offline device
[64126.311209] blk_update_request: I/O error, dev sdd, sector 923011280 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[64130.785819] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64131.243892] [UFW BLOCK] IN=eth0 OUT= MAC=dc:a6:32:04:31:6b:74:36:6d:7f:b9:c3:08:00 SRC=192.168.11.1 DST=192.168.11.17
 LEN=339 TOS=0x00 PREC=0x00 TTL=64 ID=35160 PROTO=UDP SPT=1900 DPT=51579 LEN=319
[64135.905950] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64141.026019] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64146.146167] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64146.953876] sd 3:0:0:0: rejecting I/O to offline device
[64146.960490] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64146.974117] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64146.988424] sd 3:0:0:0: rejecting I/O to offline device
[64146.995026] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64147.008047] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64147.021053] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64147.030295] EXT4-fs (sdd1): I/O error while writing superblock
[64147.037814] sd 3:0:0:0: rejecting I/O to offline device
[64147.044408] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64147.057990] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64147.072342] sd 3:0:0:0: rejecting I/O to offline device
[64147.078942] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64147.091972] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64147.104976] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64147.114168] EXT4-fs (sdd1): I/O error while writing superblock
[64147.161233] sd 3:0:0:0: rejecting I/O to offline device
[64147.167837] blk_update_request: I/O error, dev sdd, sector 923011280 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[64151.244209] [UFW BLOCK] IN=eth0 OUT= MAC=dc:a6:32:04:31:6b:74:36:6d:7f:b9:c3:08:00 SRC=192.168.11.1 DST=192.168.11.17
 LEN=339 TOS=0x00 PREC=0x00 TTL=64 ID=45099 PROTO=UDP SPT=1900 DPT=51579 LEN=319
[64151.266249] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64156.386384] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64161.506448] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64166.626570] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64171.245894] [UFW BLOCK] IN=eth0 OUT= MAC=dc:a6:32:04:31:6b:74:36:6d:7f:b9:c3:08:00 SRC=192.168.11.1 DST=192.168.11.17
 LEN=339 TOS=0x00 PREC=0x00 TTL=64 ID=57119 PROTO=UDP SPT=1900 DPT=51579 LEN=319
[64171.746730] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64176.866879] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64178.946908] sd 3:0:0:0: rejecting I/O to offline device
[64178.953505] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64178.967100] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64178.981427] sd 3:0:0:0: rejecting I/O to offline device
[64178.988018] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64179.001052] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64179.014057] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64179.023253] EXT4-fs (sdd1): I/O error while writing superblock
[64179.030738] sd 3:0:0:0: rejecting I/O to offline device
[64179.037327] blk_update_request: I/O error, dev sdd, sector 922814720 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class
 0
[64179.050901] EXT4-fs error (device sdd1): __ext4_find_entry:1531: inode #28835841: comm php-fpm7.4: reading directory
lblock 0
[64179.065167] sd 3:0:0:0: rejecting I/O to offline device
[64179.071753] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64179.084782] blk_update_request: I/O error, dev sdd, sector 2048 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[64179.097787] Buffer I/O error on dev sdd1, logical block 0, lost sync page write
[64179.106981] EXT4-fs (sdd1): I/O error while writing superblock
[64179.154842] sd 3:0:0:0: rejecting I/O to offline device
[64179.161444] blk_update_request: I/O error, dev sdd, sector 923011280 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[64181.986840] hub 1-1:1.0: hub_ext_port_status failed (err = -110)
[64187.107001] hub 1-1:1.0: hub_ext_port_status failed (err = -110)

Can someone help me to understand?