The builder needs to create a new key chain and set it to be the default one. There is no way around it.
You can change the default keychain by going to this folder with Files: /System/Library/CoreServices/Applications
Open Keychain Access and then set the default keychain in the upper left corner.
Yeah, I know that the builder needs to do it.
But, I do not know how to reset the default keychain... Before I run the server there is a keychain called "login", after launching the server this keychain vanishes and I do not know how to bring it back
EDIT:
Ok, I managed to bring back the "login" keychain by doing the following in the left pane:
Right Click > Add keychain
It opens the default folder of keychains where there was the "login" one, so I selected it and it was back.
Now, the question is:
@Erel why the "login" keychain is removed? it cannot be left where it is? if not, is not possible to edit the Build Server code to put the keychain back when the program (server) is terminated?