An error occurred while saving the commentBen P commented
We have had to generate an App password to use with SharePoint Designer as Designer is not MFA Compatible. Hopefully this solution can work here.
To create an App Password:
Click on https://portal.office.com/account/ .
( make sure to login with your account that you're going to log into designer with.
When the page loads confirm that you see your account in the top right. You should be prompted to go through MFA at this point if you have it enabled.
Click on Security & Privacy
Click on Additional Security Verification.
Click on Update your Phone Numbers used for Account Security.
Next on the top, click on App Passwords. You'll see this located on the top of the page next to Additional Security Verification.
Click on the Create Button. Name it "SharePointDesigner".
Copy the password. (place it in a text file for safe keeping)
Type in the name of a site on our farm to connect
When prompted now for login type in your account name and paste in that app password