Dropbox error 429 response when syncing

Today, I got the following error multiple times (see image)

Screenshot 2023-08-29 at 09.02.05

Googling a bit, the error 429 coming from Dropbox seems to be related to 'too many requests'.
A restart of Joplin seems to have fixed it, but still.. what does Joplin do that could generate this error on Dropbox?