No update of signatures are posssible

Hi together,

since 2 weeks following problem occures at my computer and at my labtop as well:

The update of the virus signatures is not possible because there is no connection to the server (failure message displayed).

I didn´t change anything, try to install the newest version of CIS but nothing helps.
A quick advice will be very appriciated. :-[
Thanks in advance

schillingmi

which version of CIS are you using

I try to install the latest version. It is 8.0.0.4344