A new poll survey has showed Democrat Hillary Clinton slipping against the influential Republican presidential candidates in Iowa, Colorado and Virginia.

The Quinnipiac University Swing State survey, which was released on Thursday, showed that the former secretary of state is in a close race with Senator Rand Paul but the recent controversy over her private email servers has damaged her presidential prospects against the Republican bigwigs.

Kentucky Republican Paul had declared his candidacy for the presidential election on Tuesday.

Clinton, who has still not announced her White House bid and is likely to make the same this month, is associated with all the Republican candidates in Colorado and Iowa, according to the poll.

Peter Brown, who was behind the poll, said, “It isn’t just one or two Republicans who are stepping up; it’s virtually the whole GOP field that is running better against Clinton since the last swing state survey on February 18.”

According to Brown, the drop in Clinton’s chances is due to the controversy in March triggered over her use of personal email server for official work when she was holding the post of America’s top diplomat. Republican leaders have increased the prospect of congressional hearings over the matter.

In Colorado, Paul led Clinton by a significant 44-41 percent. On the other hand, Paul managed to make a lead over Clinton by 43 percent to 42 percent in Iowa and by 47 percent to 43 percent in Virginia.

The poll showed a bright spot for the Democratic leader in Virginia, where she led all her Republican counterparts, including prominent Republican face and former Florida Governor Jeb Bush, whom she led with 47 percent to 40 percent, as compared to a 42-42 percent tie in February.

The telephonic survey, which was conducted between March 29 and April 7, involved 2,803 likely voters. The poll had an error margin of 3.3 points in Colorado and 3.2 percentage points in Virginia and Iowa.