If your company uses Slack, you can choose to restrict this type of login as shown below. 

Step 1. Team integrations 

1. Click your team's name on the top left corner to access the dropdown menu. 
2. Click Team integrations.
3. On the Team integrations page, choose Slack. 

Be sure your Slack integration is set up.

 

Step 2. Uncheck Slack

Once you're there, click Admin settings and then uncheck the Slack permission. 

 

Related

• Slack integration overview