Intermittent TCP errors in Azure function

[SimonFletcher]

Hi,

I have an Azure Function which uses library to check whois details. When running a single instance of the function all works fine, however when I have multiple concurrent instances I get intermittent errors after calling the Lookup (or LookupAsync) methods:

Error whilst reading data: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

I'm a bit out of my depth here. Any ideas what might be causing this?

Thanks!