My personal suggestion : DO NOT USE DUBOX
The service has been offered from the same company " BAIDU "which has a very bad reputation in cloud storage market. Baidu offered a similar service which started back in 2012 (It was only limited to Chinese citizerns because it needed a chinese phone number) and allowed users to upload 1 TB of files for free, but when it slowly gained some momentum with large number of users using the service, They implemented a marketing strategy called “kidnapping sales” , They didnt reduce the free users’ free space but their download speed to < 50kbps. 50 Kbps is way too less in a country that claims to have setup the first 5G network system.
This was my personal view. You can read more by doing a simple google search like “why is dubox offering free storage” or “dubox review”
GOOD LUCK, just tried to help communtiy members so that they dont get trapped in this sh*thole marketing practice.