Talks with financial investors Permira and Apollo came to an end by mutual agreement just over two weeks ago, the FTD said, referring to unnamed persons familiar with the negotiations.
Reuters report Siemens declining to comment on the issue.
Permira and Apollo had been the last potential buyers of the unit, valued by analysts a few months ago at about 2 billion euros ($2.56 billion).
Siemens's Chief Executive Klaus Kleinfeld told a news conference on November 9 that the company needed to strengthen Enterprise Networks before it could enter a partnership or sell the business. He had earlier promised to sell the division by year-end.
A few days before the news conference, sources close to the talks told Reuters that some of the last bidders had pulled out; partly because they felt the price Siemens wanted for Enterprise Networks was too high.
When asked at the news conference whether a sales process was still going on, Kleinfeld said talks were going on in parallel with the restructuring.