HTTPError 403 Forbidden

[Aihua]

Hello,

I saw "HTTPError 403 Forbidden" exceptions from time to time during
launching ads using Adwords API calls. I wonder what could cause this
kind of exception?

For example, get 403 exception when do getCampaign call and five
minutes later it's normal when do getCampaign call with same campaign
id.

Thanks,

[AdWords API Advisor]

Hello Aihua,

403 Forbidden errors are usually triggered when Google's HTTP servers
detect that there are too many incoming requests from your network
within a short period of time.

If you frequently encounter 403 Forbidden errors, I'd recommend that
you scale back on the frequency of requests that you're making and/or
spread your requests out so that they originate from different source
networks (assuming you have several networks with different public-
facing addresses).

Please note that requests from your source network to any Google HTTP
server can contribute to the traffic that triggers a 403 Forbidden
error, so if you're also using another Google API in addition to the
AdWords API that would need to be scaled back as well.

I'm afraid that I can't provide specific guidance about what the
thresholds are for triggering these 403 error responses.

Cheers,
-Jeff Posnick, AdWords API Team