Sunderland were unable to complete the signing of Portuguese goalkeeper Mika Domingues on Wednesday.
The Premier League outfit were hoping to finalise a deal before the transfer deadline but they failed to do so, despite Portugal's Boavista claiming the transfer was done via social media.
Sunderland used Twitter to provide an update on the situation, with a statement from their official account reading: "Despite the best endeavours of both clubs, a deal has not been completed for the transfer of Mika Domingues from Boavista to Sunderland AFC."
Mika - a former Portugal youth international - has been at Boavista since arriving from fellow Portuguese side Atletico CP in 2014.
While Sunderland were unable to sign Mika, David Moyes and Co. managed to bring in Didier Ndong and Jason Denayer (loan) on deadline day.
