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Canon MF645Cx suddenly stopped sending files to Synology NAS share via FTP


Hi guys. Around 3 weeks ago my Canon MF645Cx suddenly stopped being able to write scanned files to the shared folder on my NAS via FTP. It was working fine for 2 years.

  1. I did not to my knowledge change any settings to cause this.

  2. The Synology logs show that:

-User [CanonMFP] from [] logged in successfully via [FTP].

-FTP client [CanonMFP] from [] logged out the server with totally [0 bytes] uploaded and [0 bytes] downloaded.

3) The CanonMFP logs show:

Error #804 User Permissions Issue

3) NAS user account permissions for the MFP account seem correct. NAS firewall and port forwarding settings seem correct. MFP settings for the NAS FP account seem correct. I re-checked and re-entered the password for the NAS FTP user account that is linked to the printer and in the printer address book and they are correct.

So all of a sudden the Canon MFP seems to connect, but does not upload any data and the Canon logs show a #804 permissions issue despite me not being able to find what could be causing the problem.

Does anyone please have any insight before I start to lose my mind? 🙂



We appreciate your participation, though we need to let you know that your product appears to be a model that is not supported by our team here at Canon USA. While the community is welcome to chime in, the Canon Community Forum is hosted and moderated within the United States by Canon USA. We are only able to provide support for Canon products manufactured for and used within the US market.

If you live outside the United States, please click HERE and select your country to find support in your part of the world.

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