Help with zoho.crm.updateRecord Error

Help with zoho.crm.updateRecord Error

My custom function is written as follows:

leads_mm = zoho.crm.searchRecords("Leads","(Lead Status|=|Assigned for Mail Merge)");

for each lead in leads_mm
{
leadID=lead.get("leadid");
resp = zoho.crm.updateRecord("Leads",leadID,{ "Lead Status" : "Correspondence Sent", "Lead Source" : "Employee Referral" });
}

When I click "Save and Execute" after editing the script, the last line of code (beginning with "resp = zoho.crm.updateRecord") causes an error. The attached screenshot shows the error message.

I've gone over all the tutorials and can't seem to find what might be causing the error. Thanks in advance for your help !