Steps to reproduce:
When doing server updates (making use of apt), the zabbix 3.4 (deb-src) repo is causing a error in the apt update (Failed to fetch http://repo.zabbix.com/zabbix/3.4/debian/dists/jessie/main/source/Sources Hash Sum mismatch)

it looks like the problem started on the 17th of November 2017, which is the time there was changes made to the zabbix 3.4 repo.

Result:
W: Failed to fetch http://repo.zabbix.com/zabbix/3.4/debian/dists/jessie/main/source/Sources Hash Sum mismatch

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

Already did the following to try and resolve the problem:

• Cleared the apt-cache
• removed the files in /var/lib/apt/lists/

Both did not resolve the problem.

Any further help or assistance, would be appreciated.

Thanks