This article covers
How to fix this Avalara error on Chargebee: "Current theme is not supported for Avalara integration. Please use supported themes."?
You get this error when you have an Avalara Integration in Chargebee and while setting it as your preferred mode of tax calculation. Avalara integration isn't supported in Rhapsody. This needs to be changed.
This error can be seen at Settings > Configure Chargebee > Taxes > choose a country > Pick your preferred mode of tax configuration for the region > Avalara
Just to be sure check if you are using Checkout v2 version and if you have the Rhapsody theme for hosted pages. Avalara integration isn't supported in Rhapsody. Check out the limitations here - https://www.chargebee.com/docs/2.0/avatax-for-sales.html#limitations
Follow the help doc to change the theme for your hosted pages: https://www.chargebee.com/docs/1.0/themes.html
If you are using the latest version of the checkout (v3) (pop-up version), then it could be the scenario that before you switched from Hosted pages version v2 to v3, the v2 version was set to Rhapsody theme.
If you are facing the same issue on both your test and live site, Contact email@example.com so we can downgrade your Chargebee Hosted pages version from V3 to V2, so you can change the theme settings by going to Settings > Configure Chargebee > Hosted Pages. Once done, you can change the version back to hosted pages v3.
Related articles and Documentation
https://support.chargebee.com/a/solutions/articles/250468 (HPv1 to v3 migration - internal process)