After attaching a file to an ECA, the file is listed on the contact's "File" tab but the link goes to "file.pl&action=get", which returns a 404.
This link should download the actual file.
Proposed fix in PR 599: https://github.com/ledgersmb/LedgerSMB/pull/599
Proposed fix in PR 599: https://github.com/ledgersmb/LedgerSMB/pull/599