Hi @Dharmanshu_Johar, once you create a sandbox from v1.8.6, the page will change to show logs which will contain a link to the deployment for your sandbox.
Please check if this deployment is successful. Sandbox initialization is dependent on deployment.
I just created a new one (Cloud ), the earlier one was failing but now I see they are getting created.
Is there any document which tell the various stages in sandbox like the one created is still in created stage also briefs about on the initial test setup and usage for integration testing?