From Reddit - sounds like Ohio State released a generic code early and TN fans bought up tickets??!?!?
Yesterday's "season ticket holder" presale featured a code sent out to ~20,000 people that was supposed to allow season ticket holders to purchase early tickets.
Instead that code allowed anyone, with or without a season ticket account to purchase tickets.
This has lead to a ton of people who waited on general sales (today) to not have any tickets available at retail, and only buying from resellers.
Clearly some issues to work out on playoff game logistics with tickets between this, the Penn State complaints, and the Oregon Rose Bowl situation.