The IRS informed Mayweather of its intention to notify the Department of State in late March, nearly a month before the boxing legend officially announced the exhibition with the Greek kickboxer on April 23.

The IRS explained to Mayweather that the passport action is related to an unresolved seriously delinquent tax debt.

This comes against the backdrop of the back-and-forth negotiations between Mayweather and his rival, Manny Pacquiao, for a planned Sept. 19 rematch at The Sphere in Las Vegas.

Netflix announced the event on Feb. 23 as a professional fight that would count on their records, a return bout more than 11 years after their historic first fight in May 2015.

On March 28, Mayweather claimed it was an exhibition rather than a professional fight and said the venue was undecided. The Ring, however, reviewed documents signed by Mayweather that state it’s a professional fight rather than an exhibition that would take place at The Sphere.

On the April 13 episode of “Inside The Ring,” Pacquiao appeared on set and said, “I wouldn’t fight an exhibition. It’s either a real fight or nothing.”

According to multiple sources, sides for Mayweather and Pacquiao remain engaged in negotiations to finalize the event as a real fight. Sources said the venue will now shift to either MGM Grand Garden Arena or T-Mobile Arena in Las Vegas.

Mayweather is 49 while Pacquiao is 47.

Mayweather’s planned exhibition with Mike Tyson also remains in question. On Sept. 4, Mayweather announced he would meet the former heavyweight champion, but no date or location was revealed.

The announced promoter of the Mayweather-Tyson event, CSI Sports, was contracted to stage the event by April 30, per multiple sources. The Tyson camp discussed the Democratic Republic of Congo as the leading site option among other locations, sources said.

An extension to May 30 was agreed to hold the event, per sources, but holding it outside the U.S. would also become problematic given the passport issue.

Mark Taffett, head of CSI Global Live Events, didn't respond to a text message from The Ring seeking comment on the status of the exhibition with Tyson.

Mayweather owes upward of $7.25 million (between tax liens and levies) to the IRS, per the documents reviewed. Among the ways Mayweather can prevent the passport revocation, he can either pay the debt in full; reach an installment agreement or settle with the Department of Justice; establish his tax debt isn't collectible because of financial hardship or the result of being a victim of identity theft; file for bankruptcy.

Multiple attempts made by The Ring to reach Mayweather or an official representative for comment were unsuccessful.