If you get an unrecoverable error when you are trying to log an email to SIMS, this can be due to an invalid character in the email. For example "quotation marks" cannot be written back to the communication log.
This could also be due to the content having hidden formatting after being copied and pasted from Word.
The message will still send, but will need to be logged to SIMS manually by entering it directly in to the SIMS Communication log.