This is normal message, and there is no need to be alarmed about it.
In the first message, Postfix 2.8 displays an information instead of a warning. IMSVA 9.1 uses Postfix 2.7.1, so that it contains this information. In future versions, IMSVA will upgrade Postfix version to enhance this.
In the second message, FoxProxy module rejected the mail, causing Postfix to this warning. This is an expected result.