iOs 4 sometimes slows down Exchange and either does not sync or does it slowly

Apple published a newsletter with a very interesting description: Exchange ActiveSync Mail, Contacts, or Calendars do not sync or do it very slowly. At the same time, some Exchange administrators note the slow operation of servers.
Apple recommends installing the update on all phones used in the company, if possible.

The treatment is simple: you need to run Safari and download the configuration profile You need to install despite the warning about the lack of a digital signature.
After installing the profile, you can find it in Settings> General> Profile.
The essence of the profile is a change in the waiting timeout.

So think after that what you want.
I dare to assume that the phones pass authentication, and then, without waiting for a response, they send a new request. So it turns out DoS.