iPhone and iPad often drop Wi-Fi connection

[mi2428]

• 100% lost while/after uploading a large file, e.g., upload movies to dropbox from iPhone

Reassoc every 1 minute on iOS/iPadOS

Also reproduced on Android (every 2-3 minutes) and Ubuntu (> 10 minutes)

Sep 07 19:08:04 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:08:04 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:08:04 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:08:04 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: associated
Sep 07 19:08:04 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 RADIUS: starting accounting session 7B41E5189341C87A
Sep 07 19:08:04 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 WPA: pairwise key handshake completed (RSN)
Sep 07 19:09:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:09:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:09:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: associated
Sep 07 19:09:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 RADIUS: starting accounting session 0D47F6673435BB3B
Sep 07 19:09:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 WPA: pairwise key handshake completed (RSN)
Sep 07 19:10:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:10:05 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:10:06 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: associated
Sep 07 19:10:06 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 RADIUS: starting accounting session DE3F87818E432416
Sep 07 19:10:06 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 WPA: pairwise key handshake completed (RSN)
Sep 07 19:11:06 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:11:06 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:11:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: associated
Sep 07 19:11:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: associated
Sep 07 19:11:08 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 RADIUS: starting accounting session BB4CCBF5A497708F
Sep 07 19:11:08 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 WPA: pairwise key handshake completed (RSN)
Sep 07 19:12:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:12:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:12:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: disassociated
Sep 07 19:12:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 IEEE 802.11: associated
Sep 07 19:12:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 RADIUS: starting accounting session E98E618C5F9EC678
Sep 07 19:12:07 vsixpi hostapd[391092]: wlan0: STA d8:1c:79:0d:71:66 WPA: pairwise key handshake completed (RSN)

[diyfixtool]

Make sure to disconnect all accessories from your iPhone and remove the protective case.
Make sure to update your iPhone system to the latest version. (Important: Please back up your iPhone before updating the system.)
Make sure that the apps you install are from the App Store and have been updated to the latest version.
Make sure there are no potential Wi-Fi and Bluetooth interference nearby.
If you have installed a Wi-Fi assistant app, please be sure to uninstall the relevant app and see if the problem persists.
Try restarting your router and your cable or DSL modem.
Try force closing all background apps and then restart your iPhone.
Tap Settings > General > Reset > Reset Network Settings. This will restore your Wi-Fi network and password, cellular settings, and your previous VPN and APN settings.
Tap Settings > General > Reset > Reset All Settings. Your iPhone will restart and all settings will be removed, but no data or media will be erased.
If possible, try changing to a different Wi-Fi network environment to see if the problem persists.