Invalid External Rewrite
Why This Error Occurred​
A rewrite was defined with both basePath: false and an internal destination. Rewrites that capture urls outside of the basePath must route externally, as they are intended for proxying in the case of incremental adoption of Next.js in a project.
Possible Ways to Fix It​
Look for any rewrite where basePath is false and make sure its destination starts with http:// or https://.