Autofill Not Working on one web site

I confirmed under the privacy tab where all my passwords are stored that it has the correct account name, correct web address, correct username/ID, and correct password. Yet when i go to that site it only fills in the correct user ID but not the password. I’ve checked to make sure there is not more than one entry per account.What is causing the problem?

Did you check to see if there was a saved password on file for that web site?