php5.6-curl not installing?

Question

linux

Good morning! Help deal with the problem.
Can't install php module.
OS Debian
$ sudo apt install php5.6-curl
Returns

Reading package lists... Done
Building dependency tree
Reading status information... Done
Some packages could not be installed. Perhaps what you are asking for is
not feasible, or you are using an unstable version of the distribution where
the packages you requested have not yet been built or have been removed from Incoming.
The following information may help you:
The following packages have unmet dependencies:
php5.6-curl : Depends: libcurl3 (>= 7.18.0) but it won't install
E: Unable to fix errors: you have broken packages.

Did the following

$ sudo apt-get update --fix-missing
Ign:1 deb.debian.org/debian stretch InRelease
Ex:2 deb.debian.org/debian stretch-updates InRelease
Ex:3 deb.debian.org/debian stretch-backports InRelease
Ex:4 deb.debian.org/debian stretch Release
Ex:6https://packages.sury.org/php jessie InRelease
Ex:7 https://packagecloud.io/AtomEditor/atom/any any InRelease
Ex:8 security.debian.org/debian-security buster/updates InRelease
Ex:9 security.debian.org/debian-security stretch/updates InRelease
Ex:10 ftp.us.debian.org/debianbuster InRelease
Ex:11 ftp.us.debian.org/debian buster-updates InRelease
Reading package lists... Done
$ sudo apt-get install -f
Reading package lists... Done
Building dependency tree
Reading status information... Done
Updated 0 packages installed 0 new packages, 0 packages marked for removal, and 62 packages not updated.
$ sudo apt-get install php5.6-curl
Reading package lists... Done
Building dependency tree
Reading status information... Done
Some packages could not be installed. Maybe what you are asking for
is not feasible, or you are using an unstable version of the distribution where
the packages you requested have not yet been built or have been removed from Incoming.
The following information may help you:
The following packages have unmet dependencies:
php5.6-curl : Depends: libcurl3 (>= 7.18.0) but it won't install
E: Unable to fix errors: you have broken packages.

$ sudo dpkg --configure -a
$ sudo apt-get clean
$ sudo apt-get remove
Reading package lists... Done
Building dependency tree
Reading status information... Done
0 packages updated, 0 new packages installed, 0 packages marked for removal, and 62 packages are not updated.

Nothing helps. Maybe he did something wrong?
Thanks

Answer 1

The problem was that when the repository included the
deb https://packages.sury.org/php/ HERE YOUR VERSION MUST BE main
buster
jessie
stretch

Answer 2

> php5.6
> buster
There 7.3 in all fields. 5.6 was last seen on Debian 7 or 8.