Do you mean 67F or 67C? Im going to hope and assume you mean 67F since 67C would probably mean a cooked dead chameleon.
I would increase the temperature in the basking spot to at least 80F and up to as hot as 95F. That's like 32C.
According to the
Raising Kitty website:
"...a basking temp of 95 degrees f. is plenty hot for an adult... " "The basking light will provide the hottest spot in a corner at the top of the enclosure. At the bottom of the enclosure should be the coolest temp (perhaps 68 or 70 degrees) [and] in the middle will be an ambient temp of anywhere from 72 to 80 degrees."
At night the temperature should go down.
"Veiled Chameleons can withstand night time temps into the 40's. A good night time temp is between 60 and 65 degrees f."