One of the instances this error can appear if there is any rules you have configured in the suggestion index that attempt to return hits on attributes that are not existed within the suggestion index.
To troubleshoot in this situation, you can conduct the following steps:
- Disable rules from the "advanced search" section under the "Add query parameter"
- Then, search the suggestion term that returns the error message initially again
- At this point, the search should no longer produce the error and return hits as expected
The other point to note is that if you have multiple suggestion indexes, consider doing a comparison with the other suggestion indexes to check if there is any changes in the default suggestion index settings. You may need to revert the changes if this is applicable.