I collected 7 IP address and was online more than 24h.
If those nodes were offline you can't sync. The wallet could have a network condition indicator to make detecting that easier imo. Now you can go to the menu and see what your neighbor nodes are doing (i.e. do you get any packets back from them or not) and add more nodes to find online ones if needed.
You may not need 7 active nodes. My wallet got synced pretty quick with only two active nodes. You can see the syncing status from the "View Server Log" under the "Tools". For "Transacions to request = X / YYYY ( Z ms) ", as long as the YYYY is updating you are fine.