Signature check failed. Remove wrong Signature file

Ciao!
How are you?

I downloaded the sources and the image builders.
In Linksys teh source firmware just doesn't work, so I have to use the image builder.
So I have the packages in the source and the firmware from the image builder.
I can add in the PACKAGES="pkg1 pkg2 pkg3 etc" so I have a cure firmware.
But the signatures somehow wrong I get

Downloading https://cdn.corifeus.com/lede/17.01.2/packages/arm_cortex-a9_vfpv3/telephony/Packages.sig
Signature check failed.
Remove wrong Signature file.

I cannot use the source based firmware it doesn't work some setting I don't know and the the net totally not working.
So I use the image builder.

So for now i use this:

#option check_signature 1

Disabled.
So how can I make it work to so that the check_signature works with the image-builder firmware and the packages from the source.

I tried with D-Link DIR860l B1, for that the firmware works with the signature, but the fact is, that I prefer the image builder because I very easy add in pacakges I need and fits into my Flash RAM.

It is very hard to select what is good and bad so the image-builder is awesome.

So is this the only way to make it work is to disable the signature checking?

What do you think?
Thanks!

Bye dude!