Why did i get a check when i wanted direct deposit?

Please see the following excerpt from the IRS website concerning why you may have received a paper check:

I requested DD but got mailed a check:

I requested a direct deposit refund. Why are you mailing it to me as a paper check?

There are three possible reasons. They are as follows:

• We can only deposit refunds electronically into accounts in your own name, your spouse's name or in a joint account.
• A financial institution may reject a direct deposit.
• We can’t deposit more than three electronic refunds into a single financial account.

 https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions>