There is a 50MB size limit for each email sent with any Paubox Email Suite plan. If you send an attachment larger than 50MB, it will bounce back to you as an undeliverable message.
Paubox maximum message size limit is 50 MB for both inbound & outbound. For Paubox customers hosted by Microsoft 365, transcoding may occur and increase the file size by 33%, sending 36 MB or lower is recommended.
If you need to send a larger file, you can upload the file to Paubox Storage, and then share the file (either by sending a link to a specific file, or by sharing multiple files in a folder).
Note that this limit is comparable to other email platforms, including Google Workspace and Microsoft 365 default settings.