When your iPhone or iPad goes to sleep, Proton VPN stops operating on some devices. This usually results in the device disconnecting from your WiFi network. We have determined that the issue is with iOS and is beyond our control. As a result, we are unable to repair it at this time. This flaw also affects other VPN clients and providers, as evidenced by this GitHub issue created on December 1, 2019. This problem can be resolved by resetting your iPhone or iPad to factory settings and reinstalling the Proton VPN app. This will erase all information from your device. We only recommend that customers with a high threat model take this step. More information is available here.