> ## Documentation Index
> Fetch the complete documentation index at: https://docs.invoca.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Expression Syntax Error When Building Out New Signals

> A comma or other symbol in a Signal's name can trigger a false syntax error — remove it in text mode to fix the save.

**Symptoms:**

* Unable to save a new Signal.
* The following error appears: "Expression syntax error: Only a single value may be specified for signal. Use AND or OR check for multiple values."

**Cause:** Commas or other symbols within the title of a Signal name can lead to a syntax error that prevents you from saving or updating a Signal.

**Resolution:** Switch to text mode to remove any commas that may be in the Signal name.

**Applies to:** Signals

## Where to go next

* [Using Signal Builder](/s/article/using-signal-builder)