Response status code does not indicate success when inserting documents

Have have following partion id on my container: /vesselId

I am trying to add a collection of this object:

public class CoachVessel
{
    [JsonProperty("id")]
    public string vesselId { get; set; }

    [JsonProperty("imo")]
    public long Imo { get; set; }

    [JsonProperty("name")]
    public string Name { get; set; }
}

This is my code to bulk insert the documents:

 CosmosClientOptions options = new CosmosClientOptions() { AllowBulkExecution = true };
 CosmosClient cosmosclient = new CosmosClient(connStr, options);
 Container container = cosmosclient.GetContainer("CoachAPI", "Vessels");
    
 List<Task> concurrentTasks = new List<Task>();
 foreach (var vessel in vessels.Take(1))
 {
     concurrentTasks.Add(container.CreateItemAsync(vessel, new PartitionKey(vessel.vesselId)));
 }        
 await Task.WhenAll(concurrentTasks);

I get following error that does not provide much information?

Microsoft.Azure.Cosmos.CosmosException: 'Response status code does not indicate success: BadRequest (400); Substatus: 1001; ActivityId: ; Reason: ();'

Any pointers to what causes this? This is my settings:

I have same problem when deleting documents:

CosmosClientOptions options = new CosmosClientOptions() { AllowBulkExecution = true,  MaxRetryAttemptsOnRateLimitedRequests=1000};
CosmosClient cosmosclient = new CosmosClient(connStr, options);
Container container = cosmosclient.GetContainer("CoachAPI", "Vessels");


var allItemsQuery = container.GetItemQueryIterator<string>("SELECT * FROM c.id");

List<Task> concurrentDeleteTasks = new List<Task>();

while (allItemsQuery.HasMoreResults)
{
    foreach (var item in await allItemsQuery.ReadNextAsync())
    {
        concurrentDeleteTasks.Add(container.DeleteItemAsync<string>(item, new PartitionKey("id")));
    }
}
            
await Task.WhenAll(concurrentDeleteTasks.Take(3));

Throws following error: 'Response status code does not indicate success: NotFound (404); Substatus: 0;

The partition key must match a property in the document body. Change the partition key for the container to be, /id and fix your deletion code to correctly specify the partition key. E.g.,

concurrentDeleteTasks.Add(container.DeleteItemAsync<string>(item, new PartitionKey(item.Id)));