Aberdeen have refused a request from Rangers for permission to speak to Derek McInnes about their managerial vacancy.
McInnes' name has been linked with the job since Caixinha was sacked on October 26 and Rangers have now made a move to begin discussions.
However, in a brief statement on their official website, Aberdeen said: "Aberdeen Football Club has announced this evening that Rangers have contacted the club asking for permission to speak to Derek McInnes and that permission has been refused."
Compensation would have to be agreed between the sides if McInnes was to return to the club he served as a player between 1995 and 2000. STV understands that the figure is in the region of £1.1m.
The move comes after a week in which Aberdeen lost twice to Rangers in back-to-back Premiership fixtures with the Ibrox side under the temporary stewardship of Under-20s coach Graeme Murty.
Following the second defeat, a 2-1 loss at Pittodrie, McInnes made clear his frustration at the links with Rangers, saying the speculation had "dragged on and on". He had previously endorsed the comments of Aberdeen chairman Stewart Milne, who had said that the manager was happy in his current role and was "going nowhere".
The ongoing links with a Rangers move for McInnes increased after Rangers chairman Dave King told the club's AGM that a shortlist of candidates included managers under contract elsewhere.
McInnes, who previously managed St Johnstone and Bristol City, has seen his stock rise since succeeding Craig Brown at Pittodrie in 2014. He won the League Cup in 2014 and has led the Dons to the runners-up spot in the Premiership in the last three seasons.
His achievements in the north east drew the attention of Sunderland in the summer but, after Aberdeen allowed him to hold talk with the Wearside club, McInnes decided against a move, signing a new contract at Pittodrie shortly afterwards.