Etiquette: Whenever I write email I always address him 'Leonard' but I found...

I’ve a client whose name is Leonard Mayer. Whenever I write email I always address him ‘Leonard’ but I found it quite ‘dumb’ to address him ‘Leonard’. I wonder if I can address him Leon, rather than Lenoard. Whether addressing him Leon will show that I am trying to be too friendly with him . Please advise.

Good morning David, I should continue to address him as Leonard until such time as he invites you to call him Leon, or Leo. After all, he is a client, and you don’t want to offend him in any way.

Kitosdad.