ADCS problem

I found topic concerning this subject. so forget about it. Thanx.

Our client is using ADCS functionality. Several times per day they get following message on terminals:

"This message is for C/AL programmers:

This Automation variable has not been instantiated.
You can instantiate it by either creating or assigning it."

After first user gets this message he is unable to continue. Immediatelly same thing happens on all other terminals. It takes up to 3-4 minutes before they can continue working.

They are using up to 10 terminals but it happens also when they are using only 3.

It seems like timeout message.