Hi Davide,
I tried again this morning after restarting the Raspberry Pi, which I had turned off yesterday, and the router too. Now everything is working fine, and the page opens instantly.
When I wrote the last post, I had also tried restarts and turning it off and back on, but nothing worked. The logs didn’t show any undervoltage warnings, so I’m not sure if that was still the issue. I hadn’t restarted the router though, so maybe the issue was on that side.
Anyway, it’s working now.
Thanks for your reply, and please keep working to improve the stability of this service, as it’s the added value of Volumio Premium (for me) 