Change the Sizelim= keyword in the list configuration to the desired amount. The default for new lists is 30M.
- Login to Listserv
- Choose List Configuration | Edit Manually
- Change the Sizelim= setting to the desired size (or add the keyword if not already there)
- Click Update
See the List Keyword Reference for LISTSERV for more information.
Listserv Video tutorial - How can I restrict the size or type of attachments allowed on my list?