No its not a problem, you are a baron and he is only a guild guy, grow a pair man... >.<
Well, pretty much all isekai adventurer clicheés done with this chapter, get on with it... xD
some people seem to be forgetting the reason why he's joining the adventurers guild-to explore the world and to fulfill the gods request. while he can travel as a baron he wont be able to see it from a different perspective. also he now has the backing of a large group.
This guild clearly needs some form of combat aptitude test. Sure you might have some people fake being weaker. I'd imagine tho if they cared at all about their adventurers they'd make sure that at least in theory (and barring an accident) the quest they send an adventurer on is one they can complete. They could even still have them start at the bottom rank just to make sure they are up to snuff and ready for the higher rank stuff or that they won't just abandon their duties.
Ok i can understand the receptionist not knowing who Cain is, after all hes a kid who just regestered at age 12. But the Guild Chief/leader not knowing?
Even if you ignore everything hes done since comming to the capital he was granted a title for killing multipul orcs as well as an Orc General. That alone should have made the guild take notice of him.