cluster error can't access to webgui

[lesiam.phone]

and try to remove node from cluster and try add to cluster again how to fix this issue
cluster

 

[Matthias.]

Please have a look at our documentation before adding a node to a cluster.
As both error and documentation clearly state, you can't add a node containing guests.

Caution A node that is about to be added to the cluster cannot hold any guests. All existing configuration in /etc/pve is overwritten when joining a cluster, since guest IDs could otherwise conflict.

There are also several other threads about this exact problem, you might want to look through them as well.

In your title you say you can't access the webgui, but the screenshot is from the webgui and looks fine to me. If there's an issue, please describe it in more detail.