@vandekuytd 

When you are editing the parental control profile click on the highlighted + icon. A box will appear, and when you click in the text box, you will see a list of apps/sites. You should have all the major social media entries there to add:

@vandekuytd

Have tried adding sites this way.  ChromeOS basically flips me off and away it goes to sites that I have tried to block.

Extremely frustrating when clients are easily distracted to non-productive sites (TikTok, Instagram, Snapchat, etc...).

Senior management in house (wife...) getting fed up with lack of IT support (husband, me...) getting this resolved.

Again, any help is appreciated.

@vandekuytd 

Just to make sure you looked for the keyword on the list like for the example below if I wanted to block Instagram I would select it from the list:

Now, if the chrome books are still able to access have you tested on a smartphone?

The alternative would be to add a category like "Social Networking", "Online Communication", or "Media".

You can reference this site to see how TrendMicro categories a site as: https://global.sitesafety.trendmicro.com/