One: as seemingly deley do no more block the outsending it often happen that more smaller size messages are send earlier although later composed (especially confusing when using voice: other might not know and the sorting of messages is here also not of help)
Another: in cases where the sever space limits are reached messages send after stay dending even if space would be avaliable again. Seemingly only if deleting dending messages further sending and receiving would work.
(mail apps sometimes let know when limits are reached, that aside of the topic here, another time suggesting that most useful to know left space)
Just to let known: it’s a total mess if any participating part has server limit issues… receiving messages 2 month old, sorted following receiving… Some messages moved to delta-folder, some not, no chance to ever sort ones emails or messages again, no chance to ever find out received, send, or not, and no chance to figure out if anything had been missed.
Latest versions of Delta Chat support QUOTA extension and display how much space is used on the server, but the server you are using (for which you gave me an account) doesn’t seem to support it, so it’s impossible to see if you are out of space. You could try suggesting adding a QUOTA support to the admin of email server, then DC will display it.