Can't verify phone number. For help, contact your community manager [duplicate]

Question

I am trying to do paswordless registration for community users using Configurable Self-Reg Handler provided by community.

global class AutocreatedConfigSelfReg1553504253594 implements Auth.ConfigurableSelfRegHandler {

    private final Long CURRENT_TIME = Datetime.now().getTime();
    private final String[] UPPERCASE_CHARS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('');
    private final String[] LOWERCASE_CHARS = 'abcdefghijklmnopqrstuvwxyz'.split('');
    private final String[] NUMBER_CHARS = '1234567890'.split('');
    private final String[] SPECIAL_CHARS = '!#$%-_=+<>'.split('');

    // This method is called once after verification (if any was configured)
    // This method should create a user and insert it
    // Password can be null
    // Return null or throw an exception to fail creation
    global Id createUser(Id accountId, Id profileId, Map<SObjectField, String> registrationAttributes, String password) {
        User u = new User();
        u.ProfileId = profileId;
        for (SObjectField field : registrationAttributes.keySet()) {
            String value = registrationAttributes.get(field);
            u.put(field, value);
        }

        u = handleUnsetRequiredFields(u);
        generateContact(u, accountId);
        if (String.isBlank(password)) {
            password = generateRandomPassword();
        }
        Site.validatePassword(u, password, password);
        if (u.contactId == null) {
            return Site.createExternalUser(u, accountId, password);
        }
        u.languagelocalekey = UserInfo.getLocale();
        u.localesidkey = UserInfo.getLocale();
        u.emailEncodingKey = 'UTF-8';
        u.timeZoneSidKey = UserInfo.getTimezone().getID();
        insert u;
        System.setPassword(u.Id, password);
        return u.id;
    }

    // Method to autogenerate a password if one was not passed in
    // By setting a password for a user, we won't send a welcome email to set the password
    private String generateRandomPassword() {
        String[] characters = new List<String>(UPPERCASE_CHARS);
        characters.addAll(LOWERCASE_CHARS);
        characters.addAll(NUMBER_CHARS);
        characters.addAll(SPECIAL_CHARS);
        String newPassword = '';
        Boolean needsUpper = true, needsLower = true, needsNumber = true, needsSpecial = true;
        while (newPassword.length() < 50) {
            Integer randomInt = generateRandomInt(characters.size());
            String c = characters[randomInt];
            if (needsUpper && c.isAllUpperCase()) {
                needsUpper = false;
            } else if (needsLower && c.isAllLowerCase()) {
                needsLower = false;
            } else if (needsNumber && c.isNumeric()) {
                needsNumber = false;
            } else if (needsSpecial && !c.isAlphanumeric()) {
                needsSpecial = false;
            }
            newPassword += c; 
        }
        newPassword = addMissingPasswordRequirements(newPassword, needsLower, needsUpper, needsNumber, needsSpecial);
        return newPassword;
    }

    private String addMissingPasswordRequirements(String password, Boolean addLowerCase, Boolean addUpperCase, Boolean addNumber, Boolean addSpecial) {
        if (addLowerCase) {
            password += LOWERCASE_CHARS[generateRandomInt(LOWERCASE_CHARS.size())];
        }
        if (addUpperCase) {
            password += UPPERCASE_CHARS[generateRandomInt(UPPERCASE_CHARS.size())];
        }
        if (addNumber) {
            password += NUMBER_CHARS[generateRandomInt(NUMBER_CHARS.size())];
        }
        if (addSpecial) {
            password += SPECIAL_CHARS[generateRandomInt(SPECIAL_CHARS.size())];
        }
        return password;
    }

    // Generates a random number from 0 up to, but not including, max.
    private Integer generateRandomInt(Integer max) {
        return Math.mod(Math.abs(Crypto.getRandomInteger()), max);
    }

    // Loops over required fields that were not passed in to set to some default value
    private User handleUnsetRequiredFields(User u) {
        if (String.isBlank(u.LastName)){
            u.LastName = generateLastName();
        }
        if (String.isBlank(u.Username)) {
            u.Username = generateUsername();
        }
        if (String.isBlank(u.Email)) {
            u.Email = generateEmail();
        }
        if (String.isBlank(u.Alias)) {
            u.Alias = generateAlias();
        }
        if (String.isBlank(u.CommunityNickname)) {
            u.CommunityNickname = generateCommunityNickname();
        }
        return u;
    }

    // Method to construct a contact for a user
    private void generateContact(User u, Id accountId) {
        // Add logic here if you want to build your own contact for the user
    }

    // Default implementation to try to provide uniqueness
    private String generateAlias() {
        String timeString = String.valueOf(CURRENT_TIME);
        return timeString.substring(timeString.length() - 8);
    }

    // Default implementation to try to provide uniqueness
    private String generateLastName() {
        return 'ExternalUser' + CURRENT_TIME;
    }

    // Default implementation to try to provide uniqueness
    private String generateUsername() {
        return 'externaluser' + CURRENT_TIME + '@company.com';
    }

    // Default implementation to try to provide uniqueness
    private String generateEmail() {
        return 'externaluser' + CURRENT_TIME + '@company.com';
    }

    // Default implementation to try to provide uniqueness
    private String generateCommunityNickname() {
        return 'ExternalUser' + CURRENT_TIME;
    }
}

This is working for email address. But not working for mobile verification

Is SMS verification does not work for community users?