He was right.....his phones were bugged
"A tweet from President Donald Trump on Friday suggesting that he might have taped phone conversations from the White House made waves in Washington, but some former employees and a former associate said it wasn’t a surprise to them that he would mention taped conversations.
As a businessman, Mr. Trump sometimes taped phone conversations with associates and others from his Trump Tower office in New York, according to three people who say they have direct knowledge of the recordings.
Former Employees of Donald Trump Say They Saw Him Tape Conversations - WSJ