Drafts folder is not synched at android IMAP client

Symptom:
The drafts folder is not getting synched at my mobile android smartphone (android 5.1)

Good cases:
I see the sent and incoming mails nicely on my device.

Config Details:
1. I am following the guide at: https://www.zoho.com/mail/help/android-imap-access.html
SSL (always) is not available, I choosed SSL/TLS for both incoming and outgoing emails
2. All IMAP folders are marked as relevant, see https://www.zoho.com/mail/help/imap-access.html#alink2

Thanks for your advice!