This happens on a PBP session recently.
I have a goblin on a watch on a tower, but the party doesn't know this. This is an enemy base, so they rolled Dexterity (stealth) to get in.
One of the characters rolled low (9), and I noticed that they put "klank klank" sound in their in character action.
This makes me wonder, does a PC knows it rolled low when being stealthy? I know generally it does not, however in this case he failed because disadvantage of the heavy armor, so having the armor making a clanking sound seems appropriate.
Does this mean that PC knows he failed to move stealthily? If yes, this might have an unwanted ramification, like he stops and try to move stealthily again (or the whole party shush him) and let him roll for Dexterity (stealth) again.
My group does not have difficulty on keeping in character and meta knowledge out, if that is relevant, so if anyone asking for this, I don't know if this will be too meta or not.