Build error: Invalid environment variables at Object.<anonymous> (env/server.ts:14:42)

Hi,
all build methods fail with an error, seems caused by `BETTER_AUTH_SECRET`.

Tried setting into `.env` and `export BETTER_AUTH_SECRET="liWOOl****************yLT7Um1iYYaJ0o="` as per `openssl rand -base64 32`  suggested on the BetterAuth docs.

How can I help?
Thanks,
Piero
