Associate existing Contacts with the tasks while importing the tasks

Associate existing Contacts with the tasks while importing the tasks

Hi. I am trying to import some 3000 tasks in my Zoho CRM system. While Importing, in the csv file, I have added a column called "Contact ID", which I am mapping to 'Related To' field in tasks while importing. This 'Contact ID' has the IDs of contacts in my existing Zoho CRM system. When the file is imported, all the tasks are added but are not getting associated to the respective 'Contact Id' which I provided in the csv and in the Related To field while mapping. How can I associate these tasks to my existing contacts while importing?