My list won't upload
The builder says your file can't be used. Each message names the problem in one sentence; here is the fix for each.
The builder reads your file in your browser before anything is sent. When the file can't be used, the Audience step names the problem in one sentence and offers Choose another file, with Download the template beside it.
The files the builder reads
CSV, including CSVs saved with semicolons or tabs, and text exports.
Excel workbooks (.xlsx).
A file up to 20 MB, with up to 10,000 rows.
The first row holds the column names. Each row under it holds one contact, with one phone number in a column of its own.
What each message means
| The message starts | The fix |
|---|---|
| "… is over 20 MB." | Export fewer columns from your CRM, or split the list into two files and run two campaigns. |
| "… isn't a CSV or Excel file we can read." | Export it again from your CRM. CSV and Excel (.xlsx) both work. |
| "That's an old-format Excel file (.xls)." | Open it in Excel and save it as .xlsx or CSV, then upload that. |
| "That's an Apple Numbers file." | In Numbers, use File, Export To, CSV (or Excel), then upload the export. |
| "This Excel file couldn't be read." | Re-save it, or export the list as CSV. |
| "… has no contacts in it." | Put the column names in the first row and one contact on each row under it. |
| "… has" a number of rows, "and a campaign takes up to 10,000." | Split the list into two files and run each one as its own campaign. |
| "No column in … holds phone numbers." | Give each contact a phone number in a column of its own. |
| "Rows in … hold more than one contact." | Put each contact on a row of its own, with one phone number in the phone column. |
Try again
Fix the file, or export it again from your CRM.
Select Choose another file, or drop the new file on the Audience step.
What you see
the builder moves on to your file's columns, so you can match them.
Good to know
Download the template saves a sample CSV with the columns laid out.
A file that reads but has rows that can't be called is not refused: those rows are set aside with their reasons. See Why some contacts are set aside.
A campaign needs at least 25 contacts with a number we can call. When a list has fewer, the builder says so and offers Choose another file.
Need a hand? On Help, under Build it with us, select Write to the team: the script, the list or the whole campaign, written with the team.
Related
Last updated October 19, 2026
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