Oyston, 47, has admitted to five breaches of FA rules for a text message exchange in which he called a Blackpool fan “a retard”.
The FA launched an inquiry last December following a complaint by supporter Stephen Smith and in March charged Oyston with using “abusive and/or insulting words”, with reference to disability.
Oyston denied the charge and challenged it as “unlawful”, claiming the texts were private and had occurred outside business hours in response to unsolicited contact.
But the FA announced at the end of last month that Oyston’s appeal had been dismissed by an arbitral tribunal and disciplinary proceedings would continue.
FA rule E3 is the same one former Wigan chairman Dave Whelan breached late last year.
Whelan accepted a charge of improper conduct following his comments about Jewish and Chinese people and was suspended from all football activity for six weeks and fined £50,000. He was also ordered to undertake a mandatory education programme.
Oyston’s text row with Smith occurred after the chairman’s mobile number had been posted on a social media website.
The chairman later apologised for his texts, in which he called Smith a “retard” and told him to “enjoy your special needs day out”, via a statement on the club’s website.