Loomly automatically connects to the Pinterest account you are logged in within your internet browser. If you want to connect Loomly to a different Pinterest account, here is how you can proceed:
Remove your Pinterest connection from Loomly.
Log out of the Pinterest account you are logged in with.
Log in with the actual Pinterest account you want to connect to Loomly.
Go back to Loomly and connect Pinterest again to your calendar.
Otherwise, you can try connecting through a new Incognito or Private browser window.