I can't select “Description” field in Push Member Status option

I can't select “Description” field in Push Member Status option

Zoho Campaigns avails the “Description” field in Zoho CRM through which you can push your Campaigns related status.
It was ok before i change to read only the description field in the CRM.
Since I come back to read and write...
 
Since then, i have a problem t  o enable the Push Member Status option,
In   Push Campaigns reports to Zoho CRM   page,  Push Member Status as Fields   option, when i want to s  elect the   Contacts   or   Leads   option and the respective   Field   to push the campaign status, the text list of field is empty.
Can you help me ?
Thank you