topic Re: Lauch fault in DevNet Sandbox

Lauch fault

pschristides — Sat, 18 Oct 2025 15:05:58 GMT

I have been using Devnet sandbox to access Cisco Modelling Labs as a lab exercise further to Packet Tracer for my CCNA courses at:

https://devnetsandbox.cisco.com/DevNet

Unfortunately for a week now access to the sandbox has been ‘stuck’ in a launching sequence that I cannot abort.

The following error message is provided when attempting to abort launching:

Cannot terminate a Devnet connection that has been stuck in the launching mode for more than 4 days

Cisco Modeling Labs-20250408T17071841

Status: launching

Ending in 0m 0s

Running terminate is not allowed at the moment, because there’s a conflict with currently running operations. Please wait until these operations are completed.

How can I terminate process?

Please note that I can access sandbox using a Gmail address without a problem.

Thank you

P S Christides

pschristides@cytanet.com.cy

Re: Lauch fault

bigevilbeard — Sat, 18 Oct 2025 16:51:10 GMT

This happens sadly, the admin/engineering team at a Cisco will need to terminate this for you. If you was looking to run something local like PT, did you try CML free?

Re: Lauch fault

pschristides — Sun, 19 Oct 2025 08:06:04 GMT

Further to that for some time now I am unable to access Sandbox on a Windows 10 PC with the following error message:

400 Bad Request
Request Header Or Cookie Too Large

On a windows 11 machine, once accessing Sandbox, the choice to reserve CML is greyed out for quite a while.

What seems to be a problem and how can anyone contact support staff?

Thank you

Re: Lauch fault

bigevilbeard — Sun, 19 Oct 2025 10:26:42 GMT

@pschristides let me try and help

Use a private or incognito browser for accessing the sandbox, even the sandbox catalog landing page
The tile for the sandbox being grey means one of two things, the sandbox in question is not available or it is at the max capacity/reservation limit. If you hold your cursor over the tile it will show the capacity
This forum is monitored by the support team. Please note, sandboxes are provided as a free resource with no SLA or guarantee of availability

Hope this helps.