Bounce handling error

mojweb

If I manually trigger Run bounce handling/Handle the messages now, I get error after some 40 emails
AcyMailing\Helpers\BounceHelper::decodeHeader(): Argument #1 ($input) must be of type string, null given, called in /public_html/administrator/components/com_acym/Helpers/BounceHelper.php on line 543

jvstratum

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