What is the issue?

You can create and edit Custom Columns by clicking the Admin link in the upper right, then selecting the Custom Columns sub-tab. When actually adding or editing these columns, you may encounter the following error message alongside a red warning triangle icon:
 

What causes the issue?

This error occurs because the column definition field is not properly defined. There may be an invalid character, a parenthesis in the wrong place, or a different error in the formula. See the next section to learn more.

Note: Having a double space anywhere in the Conversion Type name can also cause this error.

Possible issues

There are a number of formatting issues that could be causing the problem. Check your column definition field for the following before trying to fix the issue:

• For every open parenthesis (bracket), there needs to be a closed parenthesis to create a pair. For example: ([Sales Conv.] + [Orders Conv.] is invalid, whilst ([Sales Conv.] + [Orders Conv.]) is valid.
• &, = or - cannot be part of a conversion type's column header because these are invalid characters. If this is the problem you'll need to edit the column header before fixing the Custom Column. For example: [Sales and Orders Conv.] is valid, while [Sales & Order Conv.] is invalid.
• Using [square brackets] in the Conversion Type column header results in this error, as they are treated as special characters. Removing square brackets from your Conversion Type column header fixes this issue.

How to fix the issue

To fix the problem, follow these steps:

1. Go to Admin, then click the Custom Columns sub-tab.
2. Determine what is causing the error (see the Possible Issues section above).
3. Select the checkbox next to the relevant Custom Column, then click Edit ('pencil' icon).
4. Fix the formula so that it no longer contains the problematic character, and press save.

"Column Name Not Valid For This Client"

When making Custom Column edits, you may receive an error indicating that the formula is not valid for this client. Here are a few steps you can take to resolve this issue:

1. Find your conversion type in the list box by searching for it.
2. Click on the relevant conversion type to add it to the current calculation.
3. Copy the entire formula into a text editor for easier formatting.
4. According to the conversion type in error, compare its formatting with what is set in your normal Conversion Types page. If there is an extra space anywhere or if it’s not spelled exactly as it should be, you will receive an error. 
5. Fix this and paste back in your formula and click Save.