Unable to create/delete slice, takes forever for creation and errors out

Hi all,
I have been trying to create a slice using JupyterHub with the following code:

slice_name = 'ultima2'
site = 'MAX'
num_nodes = 6
network_name='net'
try:
i = 0
ifaces = []
slice = fablib.new_slice(name=slice_name)
while i < num_nodes:
print(f'Creating Node{i}')
node = slice.add_node(name=f'Node_{i}', site=site, image='default_ubuntu_20')
node.add_component(model='GPU_RTX6000', name=f'gpu{i}')
node.set_capacities(cores=16, ram=64, disk=100)
ifaces.append(node.add_component(model='NIC_Basic', name=f'nic{i}').get_interfaces()[0])
i += 1
net = slice.add_l2network(name=network_name, interfaces=ifaces)
print("Submitting slice request")
slice.submit()
except Exception as e:
print(f"Exception: {e}")

This errors out after some time as:
Exception: Timeout 600 sec exceeded in Jupyter wait

I have the following questions:

1. How to create this slice as I often encounter this error and have to keep trying again with new names as this goes into a state where its not created and hence cannot even be deleted as well. What is the correct way to create it or solve this error once it happens?

2. How to delete this slice which is still provisioning? Using the code it says cannot delete as slice not found and I did not see anything in my slices webpage to delete it, btw the slices pages shows the following for this slice:

This slice is provisioning now. The page will automatically refresh in 23 seconds, or reload the page.
Reset Layout Download JSON Download PNG

3. How to make Jupyter wait longer than 600 sec.

Thank you.