I tried to install Chrome by downloading the debi package and then tried to install Opera the same way and got this error both times:
org.freedesktop.DBus.Error.NoReply: etc
I am running Linux Mint 19.3 Cinnamon ver 4.4.3 on linux kernel 5. 0.0-32 generic on an Acer Aspire One maxed out to 2 GB of RAM.

Please provide some context.

What precisely were the steps that you followed that led up to the error messages?

And welcome to LQ.

Thanks for the Welcome!
I downloaded Opera deb package from the Opera website and found it in the file manager. It wanted to open with the Package Manager and when clicked install I got the error I posted.

Meanwhile I did a bit more research and found this work-around which definitely worked!

sudo apt deb ./opera-stable_68.0.3618.63_amd64.deb

Still the Package Manager should have worked and didn't? Right?
Oh I tried updating the whole system with sudo apt update and updated 272 different apps
successfully first then tried the package manager again with the same error?
I still have an issue with a flakey package manager but opera is working.

Whey not use Software Manager? Its one of the System menu options, I always put a shortcut to it on my desktop.

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When I want to install a downloaded *.deb package on a *.deb system, I use gdebi.

It should be in the repos.