My phone can connect to the FFG website but when I go to "community" it says

community.fantasyflightgames.com's server DNS address could not be found

but my laptop can do it just fine.

Anyone have an idea about how to fix this

Well have you restarted your phone? Always try that first. If it's an iPhone try a hard reset.

For a long while my phone wouldn't open a box for posting, but I could always read the forums. The phone I bought last year has had no issues at all.

At a guess, you are trying on your phone on data, rather then wifi, and your phone provider has DNS issues, so cannot resolve the forum. Wifi should use the DNS from your internet connection, so would be the same. If you are using wifi, then maybe your phone is playing up and trying to use the wrong DNS.

I restarted the phone and it now works fine