In case the customer is trying to set up Salesforce, and his Salesforce account does not have Leads enabled due to them using Contacts, you need to disable Leads in MYSQL, once this is disabled manually through MYSQL customers cannot re-save CRM settings for this tenant.
First,
/opt/pbxware/sh/mysql -A admin_site
select config from 201_pbxware where ref = 'crmiservice';
{"crm":"Salesforce","apiurl":"/201/crmiservice/api","username":"","password":"","connection_data":{"CLIENT_ID":"3MVG99qusVZJwhsl8ETrWDXupgbCfM1Kg2ETCEFS95fZhip_oz9fGNkA.vtrwjM.SACasE8Xy27zclLRh55zu","CLIENT_SECRET":"77FB2DB1253E5D7B23CD9CC33AAA02D380BFB7B7FBBDB9ECDC6963C13CD6B9F5","LOGIN_URI":"https://um3.salesforce.com","CALLLOG":"yes"},"logoptions":{"loginbound":"yes","logoutbound":"yes","loganswered":"yes","logunanswered":"","upload":"no"},"crm_notused":"Salesforce","apiurl_notused":"/201/crmiservice/api"}
Once you get output, you need to update config , so copy all of the output you received and add "searchleads":"false" part as per below,
update 201_pbxware set config = '{"crm":"Salesforce","apiurl":"/201/crmiservice/api","username":"","password":"","connection_data":{"CLIENT_ID":"3MVG99qusVZJwhsl8ETrWDXupgbCfM1Kg2ETCEFS95fZhip_oz9fGNkA.vtrwjM.SACasE8Xy27zclLRh55zu","CLIENT_SECRET":"77FB2DB1253E5D7B23CD9CC33AAA02D380BFB7B7FBBDB9ECDC6963C13CD6B9F5","LOGIN_URI":"https://um3.salesforce.com","CALLLOG":"yes"},"logoptions":{"loginbound":"yes","logoutbound":"yes","loganswered":"yes","logunanswered":"","upload":"no"},"crm_notused":"Salesforce","apiurl_notused":"/201/crmiservice/api","searchleads":"false"}' where ref = 'crmiservice';
Once completed, re-test and confirm its working properly.