this outstanding authorisation on your card is most likely from a trial membership you just signed up for on some site (maybe a game site say for a Regular 5 day trial or a 5 day premium download trial). The site will begin billing you the monthly amount as soon as you sign up so that after the trial period your monthly payment is already prepared as a prepaid monthly account. Although the money doesnt actually get taken out of your bank account until after the trial period ends, its locked down by the site during the trial period. So its still in your bank account during the trial but because its locked down, you cant use it. It will stay like that throughout the trial period.
If you are happy to continue as a regular member on that site, then automatic prepayments will be taken from your bank account.
If you do not want to remain as a regular member you MUST cancel your membership, usually by logging into the site and looking for a Cancel Membership button maybe under Account details or Support, or ring them if theres a phone or chat number. Do this BEFORE the trial ends.