cms password retrieval not working anymore

A customer told me that they weren't receiving the mail for a forgotten CMS password.

I have always left everything at the default and simply entered an email address during installation. I'm sure I tested this long ago but it's literally been years since it was so simple and I have never received a complaint.

I tested 3 different sites today using the default, built in PHP function. I tried entering a new email "from" address. The only way I can get a forgotten password mail sent out is to set up the full SMPT (for me, its SSL and other info, the same I use when setting up mail on a tablet for instance.) That's fine but I am wondering why it stopped working. Call me lazy, and I'll agree, but i'm not looking forward to going to every old CMS and setting up the SMPT info. Also, my horrible host has been known to change things over the years, making me go into accounts everywhere, Sublime, Dreamweaver, etc and update. ugh. I'd prefer just the email field, done.

Any idea why the default doesn't work anymore? Am I mistaken? Shouldn't it work without having to fill in the user and password fields? Here is the current PHP version and other info showing in CMSB:

Operating System Linux 3.12.35.1418868451 Web Server Apache PHP Version PHP v5.4.37 - phpinfo >>
 Database Server MySQL v5.5.4036.1 (Max Connections: 25)

I'm doubting it's the PHP version / upgrade. I'm guessing the function is simple and wouldn't change?

another concern: The SMPT password is readable, even after saving. That is secure when saved and stored? Either way, anyone with admin rights can go to that general settings page and get my email password. :/

thanks for any help with this!