@MikeLINY,

As is the case with firmware updates on any device, it is recommended that you attempt the firmware update over a wired connection to ensure the best stability. Firmware updates are aborted often as they have the potential to brick devices, for this reason updates will always be halted if the smallest chance of an error pops up.

Firmware Downloads and Updates will also fail when done from the cloud if your device is having issues contacting the TP-Link Cloud services. Before manually updating, you may try to change the DNS server that your network is using to see if this will allow the update to proceed.

It may be possible that your Router is simply aborting the upgrade to a disconnect transfer issue. I would recommend attempting to use a wired connection with a PC and updating with the downloaded file from your support page. See the FAQ: How to Upgrade the Firmware of Your Deco

If I were to hazard a guess based on the beta firmware I have published for this device, this should be a relatively large update that may be introducing EasyMesh Networking to your router. For these updates that bring your device to what is essentially a new OS release, I would definitely recommend updating with a wired connection and with the firmware files already downloaded.