This is a traditional case. The standard functionality of Bitrix24 for sending mail does not guarantee even 98 percent of the probability that the letter will be delivered to the recipient.
Therefore, I give the solution - our integration. A lot of our customers make mass mailings through integration. In the application even there is an allocation of access rights.
Roman wrote: Bitrix24 does not have an object such as a contract. This is somewhat strange
But in Activity Stream there are business processes where you can bind the entities of CRM-objects, and then from the concrete entity you will see all the files downloaded through business processes.
Yes, sometimes there may be interruptions in the hosting of the service. To avoid the downtime of your business, we suggest switching to the server version of Bitrix24. Install Bitrix24 on your server or on the VPS server of your hosting partner. This will guarantee that both Bitrix24 and the server on which it is installed will be under your personal control.
There can be only one reason: you need to transfer each of the templates to an administrator account in the UniSender personal cabinet, and after they move to Bitrix24.