Which NWC auth page do you mean?
Could you send us more details to support@getalby.com?
Discussion
https://nwc.getalby.com is what apps like nostr:npub18m76awca3y37hkvuneavuw6pjj4525fw90necxmadrvjg0sdy6qsngq955 and nostr:npub1n0stur7q092gyverzc2wfc00e8egkrdnnqq3alhv7p072u89m5es5mk6h0 appear to use in the settings when selecting alby nwc integration. And even though the linked wallet it alby hub, the nwc conns are to the custodial wallet