Trying to send a preview and getting the error: The remote server returned an error: (500) Internal Server Error
at createsend_dotnet.HttpHelper.MakeRequest(String method, String uri, String payload)
I think I saw this before related to billing change I needed to make.
With problems like these it's very helpful to provide the exact input you are supplying to the API along with your Campaign Monitor site address. Without this information it's impossible for us to know what's happening.
Happy for me to post it in the forum or email to you?
It's up to you, however I wouldn't recommend posting your API Key in the forums. You can email support at campaignmonitor.com with your details to get some specialised help.
Checking out some logs, and it appears that the issue might be due to the preview using a list without any subscribers. Might want to check that out first
Excellent, thanks Jason.