build failed error message for a modded mob

so i was working on my mod after finding a phantom model, but whenever i try to save my mob, i get this error message:

Executing 
    Gradle task: build

Build 
    info: MCreator 2020.4.32115, forge-1.14.4, 64-bit, 7128 MB, Windows 10, 
    JVM 1.8.0_252, JAVA_HOME: C:\Users\Owner\Desktop\mcreator 
    snapshot\MCreator\jdk

> 
    Configure project :

New 
    Dep: 
    net.minecraftforge:forge:1.14.4-28.2.16_mapped_snapshot_20190719-1.14.3

> 
    Task :compileJava FAILED

C:\Users\Owner\MCreatorWorkspaces\spip\src\main\java\net\mcreator\spip\entity\SeaphantomEntity.java:300: 
    error: cannot find symbol 
 
         public void render(MatrixStack matrixStack, IVertexBuilder buffer, 
    int packedLight, int packedOverlay, float red, float green, float blue,

 
                            ^

 
     symbol:   class MatrixStack

 
     location: class Modelcustom_model

C:\Users\Owner\MCreatorWorkspaces\spip\src\main\java\net\mcreator\spip\entity\SeaphantomEntity.java:300: 
    error: cannot find symbol 
 
         public void render(MatrixStack matrixStack, IVertexBuilder buffer, 
    int packedLight, int packedOverlay, float red, float green, float blue,

 
                                                     ^

 
     symbol:   class IVertexBuilder

 
     location: class Modelcustom_model

2 
    errors

FAILURE: 
    Build failed with an exception.

* 
    What went wrong:

Execution 
    failed for task ':compileJava'.

> 
    Compilation failed; see the compiler error output for details.

* 
    Try:

Run 
    with --stacktrace option to get the stack trace. Run with --info or 
    --debug option to get more log output. Run with --scan to get full 
    insights.

* 
    Get more help at https://help.gradle.org

Deprecated 
    Gradle features were used in this build, making it incompatible with 
    Gradle 5.0.

Use 
    '--warning-mode all' to show the individual deprecation warnings.

See 
    https://docs.gradle.org/4.9/userguide/command_line_interface.html#sec:c…

BUILD 
    FAILED in 5s

1 
    actionable task: 1 executed

BUILD 
    FAILED

Task 
    completed in 13835 milliseconds

how can i fix this?