You can remove the purge valve and try to blow through it. If you can pass air through it either way, it’s bad. Dorman parts are trash. Buy an OE and be done. The p0556 could be related but most likely not.

Conditions for p0556 is engine at idle w/ brake booster vacuum less than manifold vacuum for 100ms or more. If the purge is open, it MAY set this code but I’ve personally never seen it.

If you fix your evap issue and p0556 returns, I’d check for vacuum leaks, if there are none, I’d replace the vacuum sensor on the brake booster.