Why are some of my text messages on unreadable?

[EricL-CrystalLake]

Some received text messages on my LG Cosmos display as a bunch of squares, no letters or numbers.  The first few letters are displayed okay when I scroll through the inbox, but when I open the message it's just the boxes.

[Snn5 · Accepted solution]

Some of those might indicate emojis or emoticons that were sent in the message that perhaps your phone cannot decipher.