Laptop 2. Ram slot defective?

I wanted to increase the RAM of my Acer Aspire E5-571G-52T3 laptop from 4 GB to 12 GB. So I ordered an 8 GB RAM bar from Speicher.de and installed it.

When booting up, however, I didn't have 12 GB, but only 4 GB.

So I went to troubleshooting and tried the following:

8 GB memory in the 1st slot, 2nd slot free -> starts up
4 GB memory in the 1st slot, 2nd slot free -> starts up
8 GB memory in the 2nd slot, 1st slot free -> does not start up
4 GB memory in the 2nd slot, 1st slot free -> does not start up

So it has to be the 2nd slot?

Can anybody help me further?

Well either the slot is broken or the bolt is not in the right place. So if you don't believe in yourself that you are too incapable of putting a bolt in it, it's the slot.

In that case you hardly have anything other than a guarantee to claim or just install the 8GB bar and sell the 4GB bar.

What I can think of, it could also be that the other slot in the BIOS or something is deactivated. I couldn't think of a reason why you should do that, but maybe you have to activate it somewhere or switch to dual channel or something, I don't know

It's still missing

8 GB memory in 1st slot, 2nd slot 4 GB

Otherwise maybe wrong MHz number, or only 2 identical RAM sizes are supported or both must be Single or DualSite or only SingleSite are supported or only a maximum of 8GB possible… I read up, a maximum of 16GB possible

With 8 GB in the 1st and 4 GB in the 2nd, the 4 GB are not recognized

Otherwise maybe wrong MHz number, or only 2 equal RAM sizes are supported or both must be Single or DualSite or only SingleSite are supported

Finally… Slot 2 DEFECTIVE