Billionmail/BillionMail · error

Prefixes can contain only letters, numbers, underscores, and

Error message

Prefixes can contain only letters, numbers, underscores, and hyphens

What it means

A domain-validation error thrown by BatchAdd when the requested mailbox prefix contains characters outside letters, digits, underscores, and hyphens. The prefix is used to generate batch mailbox local-parts, so invalid characters would produce unusable email addresses. This is an input validation error, not an internal failure.

Source

Thrown at core/internal/service/mail_boxes/mail_boxes.go:258

	return string(password)
}
func BatchAdd(ctx context.Context, domain string, quota int, count int, prefix string, quotaActive int) ([]string, error) {

	if prefix == "" {
		randomPre := make([]byte, 4)
		for j := 0; j < 4; j++ {
			randomPre[j] = byte(rand.Intn(26) + 97) // a-z的ASCII码
		}

		prefix = string(randomPre)
	}

	matched, err := regexp.MatchString(`^[\w-]+$`, prefix)
	if err != nil {
		return nil, fmt.Errorf("Prefix validation error: %w", err)
	}
	if !matched {
		return nil, fmt.Errorf("Prefixes can contain only letters, numbers, underscores, and hyphens")
	}

	rand.Seed(time.Now().UnixNano())

	createdEmails := make([]string, 0, count)

	timestamp := time.Now().Unix()

	//passwordEncoded := PasswdEncode(ctx, password)
	//passwordCrypted, err := PasswdMD5Crypt(ctx, password)
	//if err != nil {
	//	return nil, fmt.Errorf("Generate password md5-crypt failed: %w", err)
	//}

	mailboxes := make([]v1.Mailbox, 0, count)
	emailList := make([]string, 0, count)

	for i := 0; i < count; i++ {

View on GitHub (pinned to fc36c76c05)

Solutions

1. Resend the request with a prefix containing only A-Z, a-z, 0-9, '_' and '-'
2. Strip or transliterate non-ASCII characters from the prefix before calling BatchAdd
3. If you need dots or other characters in addresses, create mailboxes individually rather than via BatchAdd

Example fix

// before
prefix := "sales team"
BatchAddMailbox(..., prefix, count)
// after
prefix := "sales-team"
BatchAddMailbox(..., prefix, count)

var prefixRe = regexp.MustCompile(`^[\w-]+$`)
if !prefixRe.MatchString(prefix) {
    return errors.New("prefix must contain only letters, numbers, underscores, hyphens")
}

When it happens

Trigger: Calling BatchAddMailbox with a prefix such as 'team@', 'my prefix', 'café', or an empty/symbol-only string that fails the ^[\w-]+$ check (note Go's \w is ASCII-only).

Common situations: Users entering prefixes with spaces, '@', dots, or non-ASCII/accented characters in batch mailbox creation forms or API calls.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• supplier name, base URL, and API key are required
• Add up to 3 URLs
• invalid base URL format: %w
• base URL must use http or https protocol
• empty token string

AI-assisted analysis of Billionmail/BillionMail@fc36c76c05 (2026-09-05). Data as JSON: /api/errors/91b968cc929a6bba. Report an issue: GitHub.