# X_OTLP_PROTOCOL_UNSUPPORTED

## Means

the OTLP protocol requested is not OTLP/HTTP JSON

## Typical cause

`OTEL_EXPORTER_OTLP_PROTOCOL` asking for `grpc` or `http/protobuf`. This exporter speaks one wire format and no dependency ships a second — refused at construction rather than negotiated down

## Fix

unset `OTEL_EXPORTER_OTLP_PROTOCOL` (or set it to `http/json`) and point `OTEL_EXPORTER_OTLP_ENDPOINT` at the collector's HTTP receiver, e.g. `http://otel-collector:4318`

[Metrics](/error-codes#metrics)