If you mean you just have an e-mail that says "your're good" I don't think that will do. You need the lab result given from the lab showing the lab name and the lab CLIA number (i.e., the business letter head). Mine was a pdf attached to an e-mail from the lab. I uploaded that e-mail to the usvi travel portal.

Hint - print out that covid test result AND the acknowledgement showing you were accepted by the usvi travel portal (I seem to remember there was a QR code on that acknowledgement but it's been a couple of weeks so my memory may be fuzzy). Much faster to show the health department these pieces of paper than it is to fumble around with your cell phone.

Life's short - sail more!