apt-get apt-mirror Clearsigned file isn't valid, got 'NODATA'

[haiko2201]

I have a local mirror running with apt-mirror. This was fine for more then a year, since some days I am getting this error

sudo apt-get update
Holen: 1 http://192.168.0.100 trusty InRelease [246 B]
Holen: 2 http://192.168.0.100 trusty-updates InRelease [246 B]
Holen: 3 http://192.168.0.100 trusty-backports InRelease [246 B]
Holen: 4 http://192.168.0.100 trusty-security InRelease [246 B]
Holen: 5 http://192.168.0.100 trusty InRelease [246 B]litting up /var/lib/apt/lists/partial/192.168.0.100_ubuntu_dists_trusty_InRelease into data and signature failed
Ign http://192.168.0.100 trusty InRelease
E: GPG-Fehler: http://192.168.0.100 trusty InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)

if I am deleting the InRelease file it works fine also with the normal Repos of Ubuntu for archive.ubuntu.com.

After refreshing apt-mirror InRelease is back in http://192.168.0.100/ubuntu/dists/trusty/ and all the other Repo-mirros.
Than the error is back.
I found this fix..

cat fixpackage
#!/bin/bash
sudo cp -arf /var/lib/dpkg /var/lib/dpkg.backup
sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status
sudo cp /var/lib/dpkg/available-old /var/lib/dpkg/available
sudo rm -rf /var/lib/dpkg/updates/*
sudo rm -rf /var/lib/apt/lists
sudo mkdir /var/lib/apt/lists
sudo mkdir /var/lib/apt/lists/partial
sudo apt-get clean
sudo apt-get update
sudo dpkg --clear-avail
sudo dpkg --configure -a
sudo apt-get install -f
sudo apt-get update
sudo apt-get dist-upgrade

but it did not help for me.

It seems that apt-get update does not downloads all the keys and Release files.

I hoping for help. I am getting the same thing from all client computer of apt-mirror.