Nothing happens after "Awaiting download approval"

Pelion Device Management [forum moved]
1

I am using mbed EFM32GG11 board and trying to update firmware.
I have done everything according to this tutorial: https://www.pelion.com/docs/device-management/current/updating-firmware/updating-end-to-end-tutorials.html

I am testing running the campaign with: manifest-tool update device -p -D --no-cleanup

Although everything seems to be fine, nothing happens after “Awaiting download approval”. I.e, I can see in device management events log:
1:43:04 PM May 11, 2020
INFO
Awaiting download approval
Campaign:

1:43:03 PM May 11, 2020
INFO
Processing manifest
Campaign:

1:42:17 PM May 11, 2020
INFO
Device added to campaign
Campaign:

1:38:18 PM May 11, 2020
INFO
Device registered

What should I do to get the downloading started?

2

When I reboot the device, it again is able to connect to Pelion DM, but still nothing happens. (ping message can be seen in the logs)

From events log:
1:55:15 PM May 11, 2020
INFO
Manifest version reported
Campaign: campaign_name

1:55:15 PM May 11, 2020
INFO
Asset hash reported
Campaign: campaign_name

1:55:15 PM May 11, 2020
SUCCESS
Update initial value
Campaign: campaign_name

1:55:15 PM May 11, 2020
INFO
Idle
Campaign: campaign_name

1:55:15 PM May 11, 2020
INFO
Device registered