Warren Sapp -- The Nightmare Continues ... Fired From ANOTHER Job

First the NFL Network, then Bud Light ... now another company is cutting ties with Warren Sapp ... TMZ Sports has learned.

This time, the company dropping the hammer on the NFL Hall of Famer is ZYPPAH -- a mouthpiece company -- that's used Sapp as its celebrity spokesperson since 2013.

But in the wake of his prostitution arrest in Arizona, ZYPPAH tells TMZ Sports, "We will be terminating our working relationship with Warren Sapp, effective immediately."

We broke the story ... Sapp was arrested in Phoenix over Super Bowl weekend for soliciting prostitution and assault ... and although he hasn't been convicted, cops say Warren "admitted involvement in the act of prostitution" at the time of the arrest.

"While ZYPPAH fully supports the due process of law, Mr. Sapp's confirmed and admitted involvement in Monday morning's incident simply doesn't reflect the level of character we demand from our brand representatives," a rep for the company says.

"This decision was made in order to preserve the integrity of the brand and the ethical fiber upon which our core business was built."

As for Warren, he pled not guilty to the charges -- and is due back in court next week.

Sapp's been on a rough path since 2012 when he filed for bankruptcy. He eventually lost almost all of his Nike collection -- 213 pairs sold at auction for a mere $6,390.