@Sebastian Mazzey
Thank you for reaching out.
Thank you @Jackson Martins for the detailed troubleshooting above.
I think a support request will be required here to remove the subnet delegation and to delete the Virtual Network.
Could you please send an email to azcommunity@microsoft.com with the details below so that I can enable a one-time free support ticket for you in this case.
Subject : Attn Chaitanya
Thread URL: Link to this thread.
Subscription ID
Please let me know once you have done the same.
Hope this helps! Please let me know if you have any additional questions. Thank you!
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