Using ARR as a load balancer for Exchange requires special settings for Outlook Anywhere.
IIS setting
1. Open the IIS console and click Request Filtering.
![console IIS](https://rdr-it.io/wp-content/uploads/2018/12/arr-owa-1-600x201.png)
2. On the Actions menu, click Change Function Settings …
![Modify the parameters](https://rdr-it.io/wp-content/uploads/2018/12/arr-owa-2-600x195.png)
3. Change the value Maximum allowable length of the content: 2147483648 (2GB) then click OK.
![Change the value](https://rdr-it.io/wp-content/uploads/2018/12/arr-owa-3-333x400.png)
Farm configuration
1. Go to the farm configuration page and click on Proxy.
![Farm configuration](https://rdr-it.io/wp-content/uploads/2018/12/arr-owa-4-600x223.png)
2. Change the timeout value to 600 1 and the value Response buffer threshold (KB) to 0 2 and validate by clicking on Apply in the Actions menu.
![Config proxy](https://rdr-it.io/wp-content/uploads/2018/12/arr-owa-5-248x400.png)