Hi Timo,
Yes up to date means latest version as I was prompted to update in the store yesterday.
It is fixed now but I had to remove Chrome, remove access to my Google Drive in account settings, reinstall on Mac and android then allow access again and it works finally.
What happened? As I described there was a conflict with Chrome. Diarium said "logging in to Drive" and never did log in. while that was happening Chrome browser on Mac became useless. And vice versa, if I was using Chrome browser on Mac, Diarium didn't function. I consider what was happening something to do with permissions and the Diarium Mac app calling some function in Google that was conflicted with Chrome.
So long story short after setting all software up again it is working. You can mark it closed.
Thank you.