Same CalDav account on 2 phones

Since Runbox calendar cannot be shared, I configured my carddav on a second phone and created a new event on the second phone. All the existing events were downloaded to the second phone. But this new event were not uploaded to RB7 calendar or my first phone. What happened here? Thank you.

Hi. That sounds strange. Unlike systems that push I have noticed that sometimes it can take a while before an event is uploaded to your account and the more time before another device checks the account. Is this still a problem after both phones have definitely completed what they need to do?

After 3 days, the event created on the second phone was still not updated on my first phone. The event created on the first phone is updated on the second phone.