West Ham say the dispute with Sporting Lisbon over their summer pursuit of Portugal’s William Carvalho was caused by a “breakdown in communication” and the matter has now been resolved.
The Portuguese club also made personal comments about West Ham owners David Sullivan and David Gold.
In September, West Ham said they made a bid for the Portugal defensive midfielder and released emails that claim to show their official approach.
But Sporting’s communications director Nuno Saraiva questioned the validity of the leaked emails, which purport to show a 25m euros (£22.8m) offer, calling Sullivan a “liar” and a “parasite” in a Facebook post.
West Ham refuted the claims and called them “attention seeking” and considered legal action over the claims.
“West Ham and Sporting acknowledge that a breakdown in communication based in contacts between representatives from both clubs in respect of a possible transfer of William Carvalho was the cause of a misunderstanding,” said the Premier League club on Tuesday.
“Subsequent to this, the clubs have had positive communications and the matter is now resolved. On this basis, there will be no barriers to both clubs negotiating or working together in the future.”