Occasionally a Salesforce org will have its connection to Sweep disconnected - usually from a Sandbox refresh. See the below steps to re-establish the connection between Sweep and your org.
Sign in to the Salesforce environment you want to reconnect
Log In to Sweep
Click the environment selector on the top right hand side of your window
Click
Manage Environments
Disconnected:
Change Connected User: Click the three dots option next to the relevant environment and click
Reconnect
Finish connection flow