almost the same here.
After setting up Synchronisation it works. When closing Enpass and reopenig it, the Sync fails with 2 red arrows and Error code -117 is shown in the Preferences Dialog (you see the German output in this screenshot)
Going to Preferences and hitting "Sync now" works however.
Now when i close the lid of the macbook and open it again, it seems to sync forever ... or till i throw away the sync and set it up again.
The Linux Client works without any problems, the (paid) Android app also has no problems with Sync.