Work irregularly or keep stalling?

Hi All,

The situation is following:
The users send mails to the mailserver and when the server is overloaded it doesn’t send them to the Internet.
In such case I want to say to the users that the mail sending sometimes work but sometimes not.

How to say?
The mail sending works irregularly? or
The mail sending keep stalling?

Or do you have a better word for it?

Hi Attila,

I would keep the message positive rather than scarring off potential users/customers:

Please note that your emails might be delivered with a certain delay. We are constantly working on increasing our mail server capacities for you. Thanks for your understanding.

Let’s see what our fellow mods and users have to say…[YSaerTTEW443543]

TOEIC listening, photographs: Plunging into the swimming pool[YSaerTTEW443543]