CentOS 7 officially reached EOL status this past Sunday (June 30th): What to know about CentOS Linux EOL.
When an OS goes EOL, it shuts down its repos and mirrors. Servers will start to report errors like the following:
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=genclo error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
epel/x86_64/metalink | 33 kB 00:00:00
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&infra=genclo error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=updates&infra=genclo error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
* base: download.cf.centos.org
* epel: mirror.us.leaseweb.net
* extras: download.cf.centos.org
* remi-php81: mirror.team-cymru.com
* remi-safe: mirror.team-cymru.com
* updates: download.cf.centos.org
base | 3.6 kB 00:00:00
https://mirrors.wcupa.edu/epel/7/x86_64/repodata/repomd.xml: [Errno 14] curl#60 - "Peer's Certificate issuer is not recognized."
Trying other mirror.
It was impossible to connect to the CentOS servers.
This could mean a connectivity issue in your environment, such as the requirement to configure a proxy,
or a transparent proxy that tampers with TLS security, or an incorrect system clock.
You can try to solve this issue by using the instructions on https://wiki.centos.org/yum-errors
If above article doesn't help to resolve this issue please use https://bugs.centos.org/.
This means that your server will no longer receive any updates from non-InterWorx packages, including security updates.
Regarding InterWorx, we released a hotfix yesterday that will allow InterWorx updates to continue for the time being on CentOS 7 servers.
To check if you have the hotfix:
- Log in to the server at the CLI as root, either via SSH or from the terminal
- Check the InterWorx version:
rpm -q interworx
- Check the interworx-hotfix version:
rpm -q interworx-hotfix
The hotfixes for each currently supported InterWorx version are as follows:
interworx-hotfix-7.13.44.2802-1.noarch.rpm
interworx-hotfix-7.13.43.2799-2.noarch.rpm
interworx-hotfix-7.13.42.2779-2.noarch.rpm
interworx-hotfix-7.13.41.2760-3.noarch.rpm
If your server does not have the corresponding hotfix, please run:
yum clean all
yum --disablerepo "*" --enablerepo interworx-hotfix install interworx-hotfix
Again, though, that only will address InterWorx updates. You may continue to receive errors related to OS-level packages, including yum failure emails.
It is strongly recommended to migrate to a server with a supported OS.
It is not possible to do an in-place upgrade from EL7 to EL8. InterWorx must be installed on a new, fresh, minimal EL8 install.
InterWorx 7 is currently supported on RHEL 8, Alma Linux 8, and Rocky Linux 8: What are the system requirements of InterWorx Control Panel? — InterWorx documentation
EL9 support is currently in public beta, however, it is not recommended, yet, for production servers: https://forums.interworx.com/t/interworx-8-public-beta-and-el9-support/.
Also, please note, InterWorx 6 severs 100% will need to migrate to a new server with a supported OS and IW version. It is now no longer possible, at all, to update to IW7. Our support for IW6 went EOL last Sept.
If you would like a demo key to facilitate the migration, just submit a ticket to support.interworx.com and let us know. 
Information on how to migrate SiteWorx accounts can be found here: How to: Import Hosting Accounts to InterWorx — InterWorx documentation
If you have any questions or run into any issues, just submit a ticket to https://support.interworx.com and we will be happy to help you. We do not offer installation or migration services, but we assist as much as we can.
Thanks,
-Jenna
Friendly Neighborhood InterWorx Support Manager