Hi Anton,
Thank you for reaching out. With regards to your concern about the errors temporary problem with the server. The request may also time out of you're pulling extremely large data sets for which the server may return an error if it is too large. Could you please retry the request by using predicates to break up the report request into multiple, smaller requests? For example, instead of running a single report for all campaigns, you could submit multiple requests that each filter for a subset of Campaign IDs to retrieve the Keywords Performance. Please let me know how it goes.
If you are still facing any issue,can you please share the complete report definition along with customer id and please reply privately to author options while sharing the details.
Thanks,
Nirmita Patel Google Ads Team