I’ve never had the problem using my MacBook but since switching to iOS/iPad I don’t see anyone out on the circuits. Also no data is retained.
Sound like an internet issue, make sure your iPad is connected to the internet. Also check that Zwift is NOT blocked by virus protector.
Gerrie is correct. Not seeing other riders is an indication that you are not connected to the game server. I would ensure that you have an adequate connection or signal strength. Not being connected to the game server means that your ride data is also not able to be uploaded, so it’s really part of the same issue. If you have anything interfering with the connection, you would need to address that. I might suggest, for the sake of testing, that you move closer to your wifi router or outside if you are on a data connection to see if the other riders show up. Since you are just testing it at this point, you wouldn’t need to drag your trainer and bike along with you. This would likely confirm the signal strength possibility. If this doesn’t help, then as Gerrie mentioned, you would want to be sure that you don’t have a security tool/app that is blocking your connection.