These are some reasons why you may be unable to enable Zoho SalesIQ integration with Zoho CRM.
- There is already a module called “Visits” in your CRM account:
It could be a custom module that has been created or a module that has been renamed. Make sure you rename that module so you can enable the configuration.
- There could be one or more custom fields named after the default Visit Summary fields:
There are seven fields created by default in the Visit Summary section. If you have created a field elsewhere in the CRM in any of these names, you will not be able to enable the integration. These are the default field names: 
- You are using a free Zoho SalesIQ account:
In this case, you will not be able to configure the integration. Upgrade to a paid edition to resolve the issue.