I need help with my eSIM it can’t be connected

If none of the steps here work - https://support.apple.com/en-us/118669 - then you need to contact your carrier.

To use two different network providers, your iPhone must be unlocked. Otherwise, both plans must be from the same provider. Contact your network provider for more information. 

If you have an enterprise or corporate data service plan, check with your company administrator to see if they support this feature.

To activate eSIM on your iPhone Air, visit your carrier's store. Store staff will help you with a required ID check and activating your eSIM.Read more

Using eSIM with your iPhone in China mainland

You can activate an unlocked eSIM only iPhone model with network providers from all over the world. Contact your network provider to confirm ...Read more

Use eSIM while travelling internationally with your iPhone

If you can’t set up your eSIM or are having trouble using it, find out what to do.