I am running a query which loads pages of data for different tenants. Each tenant has its own database and the table has more than 500K records. I get this error from time to time and not always. It seems that it happens due to the connection not being disposed of properly but I am using the using block. Here is my code what am I missing?

The query method

public async Task<DetailedPagedResultSet<ResultSet>> GetData(Guid userId, string role, int pageNumber, int pageSize)
{
    var query = $@"";
    var parameters = new DynamicParameters();

    using var connection = _dapperContext.GetConnectionForCurrentTenant();
    await connection.OpenAsync();
    var result = await connection.QueryPagedAsync<ResultSet>(query, pageSize, pageNumber, parameters);
    
    return result;
}

The pager extension method

public static async Task<DetailedPagedResultSet<T>> QueryPagedAsync<T>(this IDbConnection connection, string baseQuery, int pageSize, int currentPageNumber, DynamicParameters parameters)
where T : PagedResultSet
{

    
    var pagedQuery = new StringBuilder();
    pagedQuery.Append("SELECT tm.*, COUNT(*) OVER () AS RowCount FROM (");
    pagedQuery.Append(baseQuery);
    pagedQuery.Append(@") AS tm LIMIT @pageSize OFFSET @offset;");

    var offset = (currentPageNumber - 1) * pageSize;
    
    parameters.Add("@pageSize", pageSize);
    parameters.Add("@currentPage", currentPageNumber);
    parameters.Add("@offset", offset);

    var data = await connection.QueryAsync<T>(pagedQuery.ToString(), parameters);

    var totalPages = 0;
    var totalRows = 0;

    if (data.IsNotEmpty())
    {
        totalRows = data.First().RowCount;
        totalPages = (int)Math.Ceiling(totalRows / (double)pageSize);
    }


    return new DetailedPagedResultSet<T>()
    {
        PageCount = totalPages,
        RowCount = totalRows,
        PageCurrent = currentPageNumber,
        PageSize = pageSize,
        Results = data
    };
}