We have identified this as a problem accepting Emojis in the messages.
Emojis are the ideograms or smileys typed directly from the keyboard, see attached. Please note that they are not the same as smileys, which are displayed as icons, whereas emojis require extended font support. On mobile devices such as phones or tablets, emojis are usually included in the form of special keyborad. In newest version of Mac OS X, Emoji icons can be included by hitting the CMD+CTRL+SPACE keys, etc.
The support for correctly diplaying emoji icons still varies across different browsers.
We expect full support for emojis to be included in our software in the coming month or two, but for now the only easy fix is avoiding using them in posts and messages at iModeler.
Apologies for any inconvenience