I apologize ahead of time, I was brought on to fix a company's website, but they asked me to do their CiviCRM. Instead, I've never done this, nor have I ever heard of it before this.

They have a few concerns, and I was hoping you guys could help me. No, I'm not getting paid, I'm volunteering to help them.

-Mail Settings: they had some email addresses bounce that are good email addresses. For example, when they send out emails, their emails bounce back. How can I fix this?

-Update CiviMail settings and website, so Unsubscribe and Opt-Out links are valid. Folks were able to use it in the first email they sent out, but now it doesn't work.

* MailChimp Extension: is there a MailChimp available to install with CiviCRM.

I did some searches on the forums to see if I can avoid asking you guys for help, but I couldn't find anything this specific. Again, I apologize, I know I'm in over my head, but I would like to learn this for my future.

Thanks!

EDIT: WordPress + Version 5.24.4

EDIT 2: This is the website: <http://crm.allparksallianceforchange.org/wordpress>