ubuntu20.04withForeman3.10 unable to create host

When I submit a new host creation, it showed Unable to save Create DHCP settings for task filed with the following error: ERF12-6899, Unable to set DHCP entry(Timed out reading data from server) for proxy foreman.test:8443/dhcp
And the error messages in forman-proxy/proxy.log were No DHCP records for IP host’s ip and finished GET /dhcp/ host’s mac with 404
Samrt Proxy show ok about DHCP which associated with and TFTP
I followed wiki’s tip about ERF12-6899 ,but this problem still happened

Expected outcome:
new host add successfully

It showed error after POST /dhcp/ about 1minute

all my operations assocaited with DHCP that delete and create will fail,when add a new host to create .cfg if showed next-server is not IPv4 try to resolve it and when delete an existing host it readtimeout

but i accomplish once a moment ago, I did not change anything. why ? I just click the submit button again and again

the first submit after i re-run foreman-installer has chance to success, late ones will fail definitly

I think 'Next-server is not IPv4, tring to reslove “foreman.test” ’ which is my computer’s hostname is a key problem, but I set --foreman-proxy-dns=true,how can i deal with it

i resolved it by restart foreman-proxy temporarily…
And I found another problem that my host created by foreman web can’t read kernel when install ubuntu

how to resolve it?

i resoled it by using fresh media from ubuntu.iso, it is something disable in installation media by default

i found foreman use @kernel to conrtorl the kernel used when installed os in the template,but there was a random string between os version and kernal name, how can i remove the random string ,because the default vmlinuz is unavild

how to deal with this, I spent two days on it , but it still error :sob: :sob: :sob:

bro, i really need help,this problem make me unrestable

there is a new problem that no valid /userdata/mac which is empty to support new host even it was created rightly and showed ok about its status.