Q: Macbook Computer Online Failure

What do yo mean by off-line?

The image shows connected.

What does diagnostics show?

Use Wireless Diagnostics to help you resolve Wi-Fi issues on your Mac - Apple Support

Hold the Option button and then click the WiFi icon - run the wireless diagnostics and leave it running in the background

Also in the same procedure - look at the information in grey - the PHY and SSID etc - post a picture of that if you can - we are interested in how many networks are around yours

If possible, please connect to another network, such as a public hotspot or the mobile hotspot created by a phone. Do you have the same problem while connected to that network?