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