I have troubles with handling non hostile social interactions with NPCs that have information or items important for the story, but who are not willing to hand it out for free.
Imagine a situation where the party comes into a tavern and the owner knows some information the party would like to acquire.
My players are alined good and normally one of them starts talking to them to get some information. After recognising that the owner is unwilling to tell them what he knows they try to persuade him. Now I let them roll d20 and they fail on the check.
Then most of the time another one tries to persuade, bribe or intimidate him. Sometimes 3 or 4 of them try to persuade the owner one after another. How can I handle this situation?
Example situation:
PCs enter a tavern, I narrate it to them explaining the owner is behind the bar cleaning mugs.
PC1: "Maybe he has information about subjectX"
PC2 talks to him: "Good day Sir, we are travellers looking for accommodation and maybe you have heard of subjectX"
Owner: "Then you came to the right place, I have enough beds for you. And about subjectX…it depends on who is asking"
PC2 tries to persuade him; He talks a bit and I let him roll a check. He fails
Owner: "It's not worth getting in trouble for giving you this information"
PC1: "Let me try talk to him" – fails too
Now PC3, PC4 and PC5 will attempt the same
Edit:
As previously discussed in the comments, I do not think this is a duplicate of:
Dealing with skill rerolls by several players
and
I failed to open a lock. Now what?
as interacting with an NPC is different than interacting with an item
Best Answer
Some attempts may automatically fail when reusing the same strategy, and some tasks are impossible to achieve anyway.
This is discussed in the Dungeon Master's Guide on pages 237:
There are certainly tasks which can be attempted over and over again for an improved chance of success, but there are those which cannot. Many players (and some DM's) do not realize that ability checks are only called for when a character attempts something that could succeed with some chance of failure. If something is guaranteed to succeed or is impossible, no check is called for: the result is a foregone conclusion without making any sort of roll.
So, use your judgment as the DM to determine if subsequent attempts at the same task would be helpful at all. In your example, it sounds like the barkeep has already made up their mind: it's too much trouble to get involved. Subsequent attempts at Persuasion are not likely to be effective, because it might be literally impossible to persuade them.
A very similar example scenario is covered right after the above passage.
If a character attempts Persuasion with the line "help us?" or "we'll pay you" and is turned down, another character attempting Persuasion immediately after that with "come on! help us!" or "but we'll pay you!" isn't going to be effective. They could come up with a dramatically more motivating line or switch to a different strategy such as Deception or Intimidation, but the previous strategy will not be effective without changes.
My advice, based on experience.
Make sure your players realize that ability checks are not magic, and they cannot make an impossible task possible. There are no automatic successes on ability checks. That is, a high roll is not guaranteed to produce a positive outcome if the difficulty class is very high, and there is no significance to a natural 20 for ability checks. In short, a conga line of ability checks does not mean someone will eventually succeed if a task is simply impossible to achieve.
If players do not internalize this after being told and try to make ability checks anyway, especially if they are belligerent and just say "I'm rolling Persuasion!" and pick up a d20 and roll it without any indication from you calling for a check, you can simply refuse to acknowledge or assess the roll and explain that the roll was not called for because the task was impossible. In my experience with this situation at a table, this only needs to happen once or twice before your players will learn proper etiquette and understand how ability checks are meant to work.
Finally, if your players are attempting the same checks over and over again, it may be because they do not see any other viable strategy. This can be due to inexperience on the player's part, but it can also occur if the DM has not given enough hints as to possibly viable strategies. Consider explicitly telling your players what other strategies they could try until they build up more personal experience, and once you believe they have the experience to come up with strategies on their own then consider peppering your narrative with additional hints about what those strategies might be. In addition, make sure you as the DM are willing to accommodate unexpected strategies you did not think of but which the players were reasonable to consider.