Credibility is one of those things that takes leaders a long time to gain – and a very short time to lose.

As far as gaining credibility, LinkedIn Learning Instructor Dorie Clark has a whole course on that entitled, appropriately, Building Credibility as a Leader. But she dedicated a video in her course to losing credibility as well; listing the three fastest ways a leader can lose the credibility they worked so hard to gain.

“These are sure-fire ways to (lose credibility),” Clark said in her course. “So smart leaders will watch for them and guard against them at every turn.”

So, what are the three fastest ways to lose credibility as a leader? According to Clark, they are:

You fail to follow through.

If you promise someone something and don’t do it, you will lose some credibility. You can mitigate it a bit with an explanation, but you still will lose some.

If you fail to come through on something big or you don’t come through and you don’t offer an explanation on why, you’ll lose a lot of credibility. And, if you do this several times, you will have almost no credibility at all.

What causes leaders to promise people things and then not come through? Clark said often it’s because they don’t want to say no; they want to please the person asking for it. That’s why such an important skill for leaders to learn is when and how to say no.

“If you want to preserve your credibility as a leader, which is one of your most valuable assets, you have to be willing to have the hard conversations now and say no, so that when you do say yes, you can really go all out and make it happen for sure,” Clark said in her course.

You consistently over-promise and under-deliver.

Do you consistently give deadlines your team can’t meet? Or set high goals that your team never reaches?

Then you’ll quickly lose credibility as a leader.

This, according to Clark, is often a symptom of the same problem as #1 – wanting to please people. Sure, someone might be happy when you give them an ambitious goal, but they’ll be very unhappy when you don’t reach it.

Or, it might be that you aren’t particularly strong at setting goals or project management. Either way, you should (mostly) hit the goals you set. Otherwise, you’ll lose credibility.

“After a while, if you keep doing this people just stop taking you seriously, which is not a good position for you to be in as a leader,” Clark said.

You don’t support your team.

Leaders don’t back their people uncritically. But they do still back their people, especially when they need it.

That means giving your people credit, instead of taking it for yourself. It means stepping in if one of your teammates hits a roadblock with an uncooperative partner. It means advocating for your people when other teams put unrealistic goals or expectations on them.

Bottom line, credibility really comes down to doing what you say you will do and advocating for what’s fair. The most credible leaders are the ones who do that – and avoid these three common pitfalls.

Want to learn more? Watch Dorie Clark’s full course, Building Credibility as a Leader.