Tvheadend

Hi guys, I've tried to install tvheadend on a fresh new raspbian jessie machine. I added the following source on the /etc/apt/sources.list file

deb https://dl.bintray.com/tvheadend/deb/ jessie release

but when i run sudo apt-get update it says

@
Fetched 144 kB in 22s (6,542 B/s)
W: Failed to fetch http://archive.raspberrypi.org/debian/dists/jessie/main/binary-armhf/Packages Hash Sum mismatch

E: Some index files failed to download. They have been ignored, or old ones used instead.
@

have you got some ideas on what is going on and how to solve the problem?
Thank you very much in advance!