I have some data in SFDC for tableau reporting ..
For normal web login for the first time we will get security password to the mail ,by using that we will login into SFDC .
By using security password and original password we are logging into salesforce .
Now with the same kind of proces,s i'm not able to connect with tableau
Is there any way avoid this authentication with out resetting salesforce authentications .
Please see the error screen shot .
I found this Knowledge Base article which seems to resolve the exact issue you are describing:
I hope this helps,