In reaction shares fell 5.62% to US$23.35 each in US pre-market trading.
Juniper now expects revenue in the third quarter to be in the range of US$1.25bn to US$1.26bn, below the previous guidance of US$1.29bn to US$1.35bn.
The company said the cut to estimates was primarily due to lower-than-expected revenue in cloud computing.
Juniper also reduced its adjusted earning per share expectations to 54 cents to 56 cents, from a previous projection of 55 cents a share to 61 cents a share.
“Although we are disappointed in our lower-than-anticipated revenue, we remain focused on operational excellence, cost efficiencies, and delivering long-term, sustainable growth," said chief executive