Error 400 When Creating Lightsail Instance: Account Cannot Use Selected Plan Size – Tickets Unanswered for 8 and 5 Days

I understand your frustration with the Error 400 when trying to create a Lightsail instance. This error indicates that your account has restrictions on the instance plan size you're attempting to use.

While I cannot directly assist with your support tickets or expedite the quota increase process, here are some options you can try in the meantime:

Immediate alternatives:

1. Choose a smaller instance plan - Try creating an instance with a smaller plan size that your account currently supports. You can always resize the instance to a larger plan later once your quota increase is approved.

2. Try a different Availability Zone - Select a different Availability Zone within your region when creating the instance, as capacity and restrictions can vary between zones.

3. Try a different AWS Region - If your workload allows, consider launching the instance in a different AWS Region where you might have different quota limits.

Regarding your support tickets: For unresponsive support tickets, you may want to:

• Reply to the existing ticket cases to bump them and show continued interest
• Check if you have the appropriate support plan that includes the response times you're expecting
• If you have a Business or Enterprise support plan, try reaching out through your Technical Account Manager (TAM) if available
• Consider opening a new case specifically asking for an update on your previous quota increase requests

The quota increase approval process can sometimes take time depending on various factors, but following up on your existing tickets should help get attention to your requests.
Sources
Resolve insufficient instance capacity errors in Lightsail - Amazon Lightsail