Why we should say "several" instead of "a several"

What kind of error is it?

Grammatical error involving article use.

Why do people make this mistake?

People sometimes confuse the use of "a" and "several". "A" is used with singular nouns, while "several" is inherently plural, leading to the incorrect combination "a several".

What is correct?

Use "several" without the article "a", as "several" indicates more than one and does not require an article.