Re: Relationship between pets
@wl2lst55ny Do you have Mods or CC? If you do, please try moving your Mods folder to your desktop and delete the localthumbnailcache.package file, plus delete any other folder in the "The Sims 4” folder with the word 'cache' in the title. (When you restart the game it will automatically create a new Mods folder.)
You can also try a game repair and make sure your game is up to date.
Are both animals healthy and in good moods? I assume you're seeing the female with the hearts animation (indicating she's in heat). Do you have at least one 'open slot' in the household size to make it possible for them to have/add one or more puppies (pet and sim pregnancies cannot occur if the household limit is already full).
There's also this Bug Report that may be of interest to you on the 'Be Nice' interaction not working on dogs:
https://answers.ea.com/t5/Bug-Reports/OPEN-CD-Be-nice-to-interaction-not-working-on-dogs/m-p/6594049#M57280
Please update us on how it goes. Thanks!
SheriGR ☕ – I don’t work for EA