Even if you take all measures to prevent input errors, users will make them anyway. Providing meaningful error messages reassures users that mistakes happen and that it isn't the end of the world.

• Use plain language: Get rid of technical jargon and passive voices, which may confuse users.
• Keep the message short: Users don't like to read, and in the face of a stressful environment, they are even less likely to read something longer than 1-2 sentences. A study by the American Press Institute shows that users are more likely to understand the whole piece of information only if the sentence contains no more than 8 words.^[1]
• Be precise: Avoid ambiguous phrases like "an error occurred," as they don't help users identify the root cause. Tell them which input contains the error and what they are expected to enter in order to solve it.
• Be polite: Avoid blaming users or making them feel stupid. Focus on fixing the problem and building trust and loyalty.