Cannot reply to text

So after contacting Apple support, the eventual solution was, in the iPhone, to navigate to settings -> messages -> send & receive and checking my iCloud account as an option to send and receive emails from. Then, in a secondary device linked to my iCloud account (my Mac in this case), going to messages -> preferences -> iMessage and opting to 'enable messages in iCloud'.

I guess I’m confused. If it was a network or battery issue, how come I can reply to any other text discussion other than this one?

Each of the solutions outlined in the provided article seemed either irrelevant to what I’m seeing in my settings or did not work. I’ll reach out to Apple support and post the solution here should they have one.