GetKeywordIdeas service long-running requests / degrated API performance

Question

Hello,

For a couple of months, we have been using the Bing (Microsoft) Ads API GetKeywordIdeas service operation to retrieve historical statistics for a specified set of keywords. These statistics are displayed within an internal tool.

Since last month we started using the GetKeywordIdeas service operation more intensively, making around 2k daily requests to store the statistics and use them for analysis. Since the beginning of our more extensive usage, we have encountered some requests that we were not able to complete within 5 minutes. This problem got worse since last Friday (26th of July), resulting in 70% of the requests taking more than 5 minutes (not completed before the 5-minute time-out has reached).

Today we performed a lot of tests and noticed that a connection was successfully established within less than 0.2 seconds. The access token and request parameters are validated and an error response is provided within not more than a second. But when authentication is successful and the request is valid, the connection stays open for a very long time and rarely finishes.

It also doesn't make sense that this would be rate-limiting behavior, as in that scenario one would not expect connections to stay open, but rather to be terminated with an appropriate response.

The requests we made contain:

• Search parameters: a maximum of 200 keywords (queries) and a language (e.g. English), location (e.g. United States, ID 190), network (OwnedAndOperatedAndSyndicatedSearch) & device (e.g. Computers).
• Idea attributes: Keyword, MonthlySearchCounts, SuggestedBid, Competition.
• Expand ideas: false

We are using the Bing Ads API ad insight service version 13 and PHP BingAds SDK (microsoft/bingads) version 13.0.19. The extensive tests are performed using the SDK version 13.0.19 & 13.0.21, and cURL.

Any ideas what might cause this? Or how it might be remedied?