Every encoder that sends RTMP needs two pieces of information: the server address where the stream goes and the stream key that says which channel it belongs to.

The server address looks like a web address that starts with rtmp or rtmps, and it is usually the same for every user of a platform.

The stream key is a long private code that identifies your channel or event, and anyone who has it can broadcast in your name.

You find both in the live or broadcast settings of the platform, and many platforms let you copy each one with a single button.

The most common mistake is pasting the key into the server field or the address into the key field, so check that each value is in its own box.

Another frequent cause is an invisible space at the beginning or end of the copied key, which makes the platform reject an otherwise correct code.

Some platforms create a new key for each scheduled event, so a key that worked last week may no longer be valid for today.

If the platform offers a backup server address, use it only for a second encoder, not as the main address of your only feed.

Addresses that start with rtmps use an encrypted connection, and an old encoder that does not support it will fail with a connection error.

An error saying the encoder cannot reach the server points to the address or your network, while a quick disconnect after connecting usually points to the key.

Corporate and venue networks sometimes block outgoing streaming ports, so test from the same network you will use on the day.

SRT does not use a key field in the same way, and the identity of your stream is carried by a stream identifier and an optional passphrase instead.

WHIP, used for browser and low delay ingest, combines the address and the authorisation into one link with a token.

If you suspect your key has leaked, reset it in the platform and paste the new key into every encoder that uses it.

Store your keys in a password manager rather than in a shared document, because a screenshot of your encoder settings can expose them.

When you stream to several platforms, label each key with its platform and event, so you never send the wrong show to the wrong channel.

A key copied from an email or a chat can pick up formatting characters, so paste it into a plain text editor first if a correct looking key keeps failing.

Most encoders show the last error in a log window, and reading that line tells you far more than retrying the connection again and again.