LinuxQuestions.org - [SOLVED] E: Impossible to fix problems, you kept (hold) broken packages.

Hey guys,
I am looking for help to solve the problem below.
Debian 10.9 installed from livecd.
New installation. After installing the system, running the apt-get update and upgrade commands does not return any errors.
Can anybody help me?

I can't install packages.
I always get the error message:
E: Impossible to fix problems, you kept (hold) broken packages.

I've followed other tutorials but to no avail.
I executed the commands below:

dpkg --configure -a
apt-get install -f

At Synaptic, I tried to fix broken packages. But Synaptic warns that it cannot fix it.
E: Impossible to fix problems, you kept (hold) broken packages.
E: Error, pkgProblemResolver :: Resolve generated failures, this can be caused by held packages (hold).

At no time did I check a package to "hold".

The error messages are as follows:

# apt-get install git
Reading package lists ... Done
Building dependency tree
Reading status information ... Ready
Some packages could not be installed. This may mean that
you requested an impossible situation or, if you are using the
unstable distribution, that some required packages have not been
created yet or have been removed from "Incoming".
The following information can help to resolve the situation:

The following packages have conflicting dependencies:
git: Depends: liberror-perl but not installable
E: Impossible to fix problems, you kept (hold) broken packages.

# apt-get install mariadb-server mariadb-client
Reading package lists ... Done
Building dependency tree
Reading status information ... Ready
Some packages could not be installed. This may mean that
you requested an impossible situation or, if you are using the
unstable distribution, that some required packages have not been
created yet or have been removed from "Incoming".
The following information can help to resolve the situation:

The following packages have conflicting dependencies:
mariadb-client: Depends on: mariadb-client-10.3 (> = 1: 10.3.25-0 + deb10u1) but will not be installed
mariadb-server: Depends on: mariadb-server-10.3 (> = 1: 10.3.25-0 + deb10u1) but will not be installed
E: Impossible to fix problems, you kept (hold) broken packages.