Hello @s.pgx06, welcome to Thunkable! 
The 2 testing APK Downloads per Month in the Free plan means that these APKs will expire after 72 hours.
You can find more information on our pricing page: Pricing | Thunkable
Be sure to check out How to ask Great Questions v2.0, the Community Guidelines, and our Getting Started Guide to make the best of your Thunkable Community experience!