ERR_J. int—(Inquir.) an error code usually received during e-mail conversations, when a dialog partner sends the letter “J” as if it were punctuation or would carry some other special meaning. Said sender uses most probably MS Outlook.

This error signals, that the sender should be made acquaintance with proper smiley characters. For ease of use, please help yourself to the following snippet:

    ┌✁──┐
    │   │
    │ ☺ │
    │   │
    └───┘

See also Wingdings and What do we have Unicode for?.