I am writing to you because I am regretful to inform you that I will have to cancel our coffee meeting (Meeting subject) tomorrow morning (date and time) due to my being ill. (Show actual problem and situations). I do wish that I could go because I was quite looking forward to seeing you and catching up with you. I guess we will have to reschedule for another time when is more convenient.
I have a funny feeling that we will have to wait awhile we both are very busy with our work. Again I must apologize for not being able to meet you and sorry for the inconvenience. I hope to see you soon and please take care.