Here is an email: Hey Mat! How have you been? I have been trying to call you to chat, but can't get through to you. Is everything ok? I wasn't sure exactly when you were going to Portland, so maybe you are there now. If you don't want me to call, please let me know. I hope all is well. Please write me and let me know what's up! Christine:)
What is a potential subject line for this email?
Where are you?