Hi, I'm getting this error message. Has anybody else seen it / now what it relates to?
That error message is coming from Google's API and not the Supermetrics side. This may be due to that your query is too heavy for Google analytics API. This is their documentation about the situation:
Handling 500 or 503 responses
A 500 or 503 error might result during heavy load or for larger more complex requests. For larger requests consider requesting data for a shorter time period. The frequency of these errors can be dependent on the view (profile) and the amount of reporting data associated with that view; A query that causes a 500 or 503 error for one view (profile) will not necessarily cause an error for the same query with a different view (profile)
One solutions could be dividing your query into smaller patches, for example with a shorter time period or fewer metrics in one query.
Also check if you have unused queries under the SupermetricsQueries tab in your sheet, and delete any unnecessary ones so they are not refreshed along the other queries.