The file '...\duplicati-xxx.dlist.zip.aes' has not been found

How can I recover from the error “the file ‘…\duplicati-xxx.dlist.zip.aes’ has not been found”?
(translated from Italian: non è stato trovato)

Description, please. What are you trying to do? Do you recall what you did, and what happened when? Knowing only the very generic error message does not give any context to start discussing a recovery.
EDIT: What storage type is the destination, and is that file truly missing, or does Duplicati just think so?

Sorry for my laconic message. The last days were a bloodbath for me.
I passed from adsl to vdsl. I’m forced to use my provider modem.
I disconnected my backup disk from my previous router and connected it to the new one. With duplicati, it was a disaster. I got a lot of errors and all my jobs failed. So i decided to create a new job and start it from scratch. But even this one failed giving the file …\duplicati-xxx.dlist.zip.aes has not been found error.
Eventually I understood the source of the problem: the modem (zyxel VMG8825-T50K) converts all filenames to lowercase before writing to the usb disk. So, duplicati is unable to find duplicati-20200611T070518Z.dlist.zip because it was previously written as duplicati-20200611t070518z.dlist.zip.
Now I’m trying to organize my bakup jobs in another ways…

Phew. Sorry about the troubles, and I’m glad you were able to figure it out. That lowercasing is not polite.