[MM3-users] 'Failed adding message' error when migrating a list from mailman2 to mailman3

Hello,

I'm in the process of migrating some of the lists from mailman2 to mailman3. I'm getting the below error message when I migrate a particular list.

*2%Failed adding message <mailman.2.1593699619.32248>: 'ascii' codec can't encode character '\ufffd' in position 252: ordinal not in range(128).*

I ran the check_hk_import script before migrating and it was not giving any error. Any idea how to fix this?

Kind regards, Prasanth