Error `unknown encoding: iso-8859-1http-equivcontent-type`

[BananaAcid]

Reading this, it seems the corresponding mails are not saved, if this error appears - is that correct?

MailboxClient.saveEmail() failed
unknown encoding: iso-8859-1http-equivcontent-type
...
MailboxClient.saveEmail() failed
unknown encoding: windows-1252http-equivcontent-type
...
MailboxClient.saveEmail() failed
unknown encoding: _iso-2022-jp$esc
...
MailboxClient.saveEmail() failed
'ascii' codec can't decode byte 0xfc in position 16: ordinal not in range(128)

[BananaAcid]

Simply dumping to a text file in that case would at least backup the content for manual handling.

Any possible solution?

[polo2ro]

MailboxClient.saveEmail() failed
unknown encoding: utf-8*fr

[BananaAcid]

unknown encoding: windows-874