What does it mean when you see a "Request access" page?
If you’re seeing a "Request access" page, it’s likely that the person who shared the folder sent the invitation to an account that you don't regularly use. Or they may have sent the invitation to the wrong person.
When someone shares a file or folder, they share it with a specific Dropbox account. Only the account owner can access the content.
How to fix the "Request access" error
Click Request access. Once the sender approves your request, you can view the shared content.
Or, you can log in to the account that the sharer originally invited.
What happens when you don't have a Dropbox account or you’re not logged in?
If you don’t have a Dropbox account or you aren’t logged in then you’ll be prompted to log in or create an account when you try to access shared content. If you don’t have a Dropbox account, you’ll need to create one to access the shared file or folder.
How to fix it
You can log in to your Dropbox account or create an account to see the shared content.
If you don’t want to sign up for an account, ask the sharer to send a shared link instead.
Why can't people accept the invite to my shared folder?
If you’re having trouble sharing a folder, it’s possible that the people you’re sharing with don’t have enough space to accept the invite. If you’re having trouble joining a shared folder that someone invited you to, it’s possible the folder is larger than the remaining available space on your account.
Why does Dropbox say I need to upgrade my account to access a shared folder?
Each shared folder member needs to have enough space in their account to accept the invite to a shared folder. Shared folders require space in each account, since accepting an invite to join a folder means you’re adding it to your account as well.
If you are seeing a "Could not add to Dropbox" message, it’s likely this is the reason.
For example, you have a 2 GB Dropbox account, but only have 1 GB of available space. If someone shares a 3 GB folder with you, you won’t be able to accept that invite. You’ll either have to earn more space, upgrade your account, or ask the person sharing to reduce the size of the folder.