I’m having trouble downloading. Sorry not having trouble downloading but having trouble opening because I already have purchased the product but have a new phone. Don’t know what to do.
Are you using the same Google account on your new phone?
When you purchase CCleaner Android through the Google Store then you don’t get a licence key but instead it is linked to the Google account that you were using when you purchased it.
When you are setting up a new phone if you don’t tell it an existing Google account to use it will create a new account for you.
(Many people have a different Google account for every Android phone they have ever owned - It got to be a problem, so every few years Google wil delete any old accounts that haven’t been used for years).
So if you are using a new Google account on your new phone then you can download a new Free version of CCleaner, but it won’t be Pro for that new Google account because your purchase is linked to the older Google account.
Try logging into your old Google account on your new phone.