Problem accessing network from Quick Look Preview Extension

I have created an iOS Quick Look Preview Extension which gets called by iOS whenever the user does a Spotlight search and previews a result from my app. The preview loads fine, but when I try to access a cloud file from within the extension it fails with DNS error, saying

Operation not permitted
.

I have found that on MacOS I need to disable sandboxing or, if using sandbox, give permission for network access, but this is iOS. There are no such settings here. How can I make it work?


Log output

2019-04-03 10:42:20.809768+0200 QuickLookPreview[7655:3650321] dnssd_clientstub ConnectToServer: connect()-> No of tries: 1

2019-04-03 10:42:21.815704+0200 QuickLookPreview[7655:3650321] dnssd_clientstub ConnectToServer: connect()-> No of tries: 2

2019-04-03 10:42:22.821499+0200 QuickLookPreview[7655:3650321] dnssd_clientstub ConnectToServer: connect()-> No of tries: 3

2019-04-03 10:42:23.827993+0200 QuickLookPreview[7655:3650321] dnssd_clientstub ConnectToServer: connect() failed path:/var/run/mDNSResponder Socket:4 Err:-1 Errno:1 Operation not permitted

2019-04-03 10:42:23.828797+0200 QuickLookPreview[7655:3650321] [] nw_resolver_create_dns_service_locked [C1] DNSServiceCreateDelegateConnection failed: ServiceNotRunning(-65563)

2019-04-03 10:42:23.831035+0200 QuickLookPreview[7655:3650321] TIC TCP Conn Failed [1:0x283aea040]: 10:-72000 Err(-65563)

2019-04-03 10:42:23.833948+0200 QuickLookPreview[7655:3650323] Task .<1> HTTP load failed (error code: -1003 [10:-72000])

2019-04-03 10:42:23.834811+0200 QuickLookPreview[7655:3650323] Task .<1> finished with error - code: -1003