Partner and free trial sandboxes might have a usage limit for Solr. The following message can appear in the logs:
Exception: SolrNet.Exceptions.SolrConnectionException
Message: {"message":"Limit Exceeded"}
Source: SolrNet
at SolrNet.Impl.SolrConnection.Get(String relativeUrl, IEnumerable`1 parameters)
...
Nested Exception
Exception: System.Net.WebException
Message: The remote server returned an error: (429).
Source: System
at System.Net.HttpWebRequest.GetResponse()
...
The issue occurs because each user is limited to 30,000 requests per month and a maximum index size of 512 MB. To increase these limits, a paid subscription is required.
To address issues related to these limitations, it is recommended to review your implementation to optimize Solr usage.