Starting Oct. 20, 2020, the OpenDNS resolvers no longer support queries for the special 'ANY' query type. The 'ANY' query type is a special query type which returns all records of all types known to the name server. The responses for a given ANY query type can be unpredictable, as the resolver will only return those records it already has in its cache.
Because the response for an ANY query type can contain multiple resource records, the size the response typically is larger than the request itself. This means that ANY query types are often abused to perform DNS amplification attacks.
As there are few legitimate uses for ANY query types, and given the potential for abuse, the OpenDNS resolvers will no longer return records for this query type, and instead return a NOTIMP response. This is similar to the behaviours of other major recursive DNS providers.