Kmail retrieval problem

Today’s update has resulted in a fail for 2 of my 5 mail accounts - both of which are on the same server.
The error message is “Unable to fetch item from backend (collection -1):Unable to contact resource”

I’m unable to access the settings for those accounts. The receiving entry shows "Retrieving folders (0%)’
Attempting to modify the receiving account settings results in a ver brief display of a small box - too fast fro me to read thwe contents.

I’m using an up to date version of Neon , Kmail version 6.1.0 (24.05.0).

The problem is not experienced on using Thunderbird to access the same accounts