Gayoom was sentenced to one year and seven months in prison for obstruction of justice when he refused to hand over his mobile phone during a police investigation, Efe news reported.
But the High Court ruling said that the 82-year-old former strongman's trial in the criminal court was conducted in "violation of procedure".
The High Court also said that the criminal court's order to cancel Gayoom's license to practice law and preach Islam was "unlawful".
Gayoom was found guilty in July but was freed on bail following the presidential election victory of opposition candidate Ibrahim Mohamed Solih.
Gayoom was arrested during a state of Emergency in February after the Supreme Court ordered the release of political prisoners and the reinstatement of 12 opposition lawmakers.
He was among dozens jailed for an alleged coup plot against the government of his half-brother and defeated President Abdulla Yameen.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
