From what you have described so far it potentially sounds like an issue with the laptop?
Have you tried a different one?
Have you tried directly with the ethernet cable?
More info on our help and support page: WiFi Connectivity and Troubleshooting
Are you able to try a different laptop?
There is limited support we can provide here on our public forum with the info you've provided, from here the next step would be to contact the Optus Technical Support team to determine if it is a problem with the Optus connection.