X_OTLP_ENDPOINT_INVALID
Means
the OTLP collector endpoint is missing or malformed
Typical cause
OTEL_EXPORTER_OTLP_ENDPOINT unset with none passed, a value that is not a URL, a scheme that is not http/https, or the collector's gRPC receiver on :4317 — OTLP/HTTP JSON is served on :4318, and an exporter pointed at the wrong port drops every batch with a transport error and no metrics
Fix
set OTEL_EXPORTER_OTLP_ENDPOINT=http://otel-collector:4318, or skip the exporter when tryOtlpEndpoint('<signal>') is undefined