The size limit of files that can be sent through FedConnect is 25 MB per individual file, or 100 MB per response or message.
For example, a user cannot submit a response that contains an attachment 40 MB in size, however they can submit a response that contains two attachments each at 20 MB in size. In addition, the user would not be able to submit a response that contains 6 attachments each at 20MB in size, as that would exceed the 100 MB submission limit.
Below are two examples of how the file size limits are noted in FedConnect on different pages.