Whenever you connect to a WiFi network, that network will be remembered and your Mac will automatically want to connect to that network again if the network is available and whenever you are in its vicinity. sometimes all you need to do is remove the network from your Wi-Fi settings and re-connect. Here’s a step-by-step guide.
Step #1 – Open Network Preferences
Step #2 – Select WiFi in the network panel
In the network panel that pops up, select WiFi from the menu on the left and then click on the Advanced button at the bottom right of the window.
Step #3 – Select the WiFi network you wish to delete
Ensure that the Wi-Fi tab is selected and then select the network that you wish to delete/forget and click on the minus icon at the bottom of the list. And that’s it, you’re done, your network is forgotten.