The ASA said it expected to see evidence that Au Vodka had taken appropriate steps to limit the likelihood of children or young people seeing their ads.
Noting that the minimum age required to create a TikTok account was 13, the ASA said the screenshot of Strafford's followers did not include data for any followers aged between 13 and 17.
It said it was therefore unable to say what percentage of her followers were under 18.
"We considered overall that the [Love Island] TV series was popular with young people, including under-18s, and that a number of individuals who were under the age of 18 with TikTok accounts were therefore likely to interact with content related to Love Island on the platform.
"Even if those individuals did not follow Ms Strafford, we considered it was likely that the algorithm would determine her posts to be of interest to them, meaning they would appear in their 'For You' page.
"In the absence of specific targeting tools and relevant demographic data being provided, and in view of the way in which users engaged with TikTok, we concluded that insufficient care had been taken to ensure that ad was not directed at people under the age of 18."
The ASA also investigated complaints about two AU Vodka ads on Facebook, including a video showing another influencer, Kai Cenat, opening a box containing a bottle of Au Vodka and drinking it.