laptop2d already said how you can fix the filter, but I'd like to explain what is wrong with your design.
There are two problems. Firstly, both filters are filtering a bit on the intended passband. In the middle of the passband both filters have 1.7 dB of attenuation, if you simulate them separately. Adding those together you get 3.4 dB attenuation.
Secondly, the second stage is loading the first stage. Output impedance of a passive filter is high, and the load connected to it must be much higher in order to not affect the filter. Now the second stage is the load for the first stage. Their impedances are in the same order of magnitude, thus the second stage affects the first stage. Increasing the impedance of the second stage mitigates this problem slightly.
I tried increasing the RI to 100k and reducing CI to 47.9 pF, which increases the impedance but keeps the frequency, and got exactly what is expected, -3.4dB at the middle of the passband. This doesn't fix the cut-off frequencies though.
The cut-off frequency of the high-pass filter is too low because attenuation of the low-pass filter is "fading away" at that frequency. And vice versa.