According to Google's forum for reporting bugs within Android, some developers are reporting that their devices running Android 5.0 won't connect to Wi-Fi networks.
The thread started on Oct. 17 with the most recent post published on Nov. 13, as blog Phone Arena spotted.
The developer that filed the original complaint says the Nexus 5 he or she had been using would save the Wi-Fi network after the password was entered, but would never actually connect to the network. More recent reports from Nov. 13 indicate the same problem has been occurring since mid-October.
It seems like most developers experiencing this problem are using Lollipop on a Nexus 5 running the build LRX201. This is an official build from Google that reflects the final version of the software - it's not a developer preview edition.
For what it's worth, the Nexus 6 Google sent us is running on a different build (LRX21I) and didn't have any issues with connecting to Wi-Fi networks. It's possible that this problem is exclusive to a specific version of Lollipop on the Nexus 5 that may not be completely up to date.