We are having the same problem - only on wireless though. When I try to join from my device using data, just fine. However we know our modem is working perfectly (even called the provider to do a health check and it's 100%). Very odd - my kids have no data access and can only access via wireless on their devices and so they can't get on. Hope this is solved soon.
Same with us - but only on wireless for whatever reason. When I use my device and turn off wireless and use data, no issues. Hoping for a fix soon. Looks like many others are experiencing the same...