Ulster's hopes of signing South Africa fly-half Elton Jantjies have been dashed by the IRFU because he is not an Irish qualified player.
The 27-year-old plays for the Lions in Super Rugby and has been capped 23 times by the Springboks.
The IRFU has the final decision on player recruitment and it has rebuffed Ulster's plans.
Ulster are seeking a replacement for Paddy Jackson, who had his contract revoked after being cleared of rape.
Jantjies made his international debut in 2012 and he holds the record for the most penalties in a Super Rugby game with nine.
Ulster finished the season with Johnny McPhillips as their only recognised fly-half after Jackson's departure in April.
Leinster's number two fly-half Joey Carbery has been linked with a move to Ulster although a summer switch to Munster is also a possibility.
Bringing in Jantjies would have been a major boost for Ulster as they seek to rebuild under new head coach Dan McFarland.