Grindel, who promised greater transparency after taking over in April 2016, apologized for accepting a watch worth about 6,000 euros ($6,700) from Ukrainian oligarch Grigoriy Surkis - a UEFA vice president and executive committee member at the time.
"Everyone who knows me knows that I am not greedy and have been dealing with compliance issues for years," Grindel said in a statement issued by the federation. "Mr. Surkis had no financial interest in the DFB (German federation). He never asked me for any support, then or after. It was clear at the time that he would not run again for UEFA's ExCo, to which he no longer belongs. There was and is no conflict of interest for me."
The federation said vice presidents Rainer Koch and Reinhard Rauball would take over on an interim basis until September. Koch and Rauball also took over after Grindel's predecessor, Wolfgang Niersbach, stepped down in November 2015 amid the fall out from allegations that Germany's bid to host the World Cup in 2006 was helped by bribery. Niersbach's predecessor, Theo Zwanziger, stepped down in 2012.
Grindel's tenure as president was the shortest in the 114 years of the federation. On Monday, the 47-year-old Grindel avoided the red carpet at the opening of the German soccer museum in Dortmund. Grindel was accused by German weekly magazine Der Spiegel last week of failing to declare additional income of 78,000 euros ($87,000) for being chairman of the federation's subsidiary media management company in 2016 and 2017 - on top of his regular salary as president.
The federation issued a statement to reject the accusations, saying Grindel took on the position with its subsidiary company only after he became president, and so was not obliged to declare the earnings at the time.
But criticism of Grindel was growing louder. "When you're in such a position and such things come to light, you should at last have arguments to put them aside as soon as possible," former West Germany midfielder Lothar Matthaeus said. "The DFB has been on shaky ground before."
Grindel was already under fire for his clumsy attempts to engage with fans while increasing the commercial appeal of German soccer. Monday night games, late kickoff times, and a ban on pyrotechnics have all proved unpopular with fans, who frequently display banners at games criticizing the federation.
The former federation treasurer also emerged badly from his ham-fisted attempts to handle the controversy of national team players Mesut Ozil and Ilkay Gundogan posing for photos with Turkish President Recep Tayyip Erdogan before the 2018 World Cup.
Ozil quit after the tournament, saying he was being made a scapegoat for the team's poor performance and a target for racist abuse - and he was particularly scathing of Grindel, who subsequently expressed his regret over his handling of the matter.
Grindel was criticized for agreeing to a hasty contract extension with Germany coach Joachim Loew after the tournament, while he recently complained about Loew's decision to drop Mats Hummels, Jerome Boateng and Thomas Mueller from the team - before doubling back.
Grindel was also embarrassed in 2017 when a scheme to allow China's under-20 team to play against fourth-division clubs was abandoned because of protests from supporters displaying Tibetan flags. Andreas Rettig, managing director of second-division club St. Pauli, said at the opening of the new soccer museum that Grindel would not get a place in its hall of fame.
"The DFB's appearance," Rettig said, "has long been in need of improvement."
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