While starting the server (hosted by GPortal), following error occurs:

[10:34:36] [main/WARN] [minecraft/Main]: Failed to load datapacks, can't proceed with server load. You can either fix your datapacks or reset to vanilla with --safeMode
java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Java heap space
at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:396) ~[?:?] {re:mixin}
at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2073) ~[?:?] {re:mixin}
at net.minecraft.server.Main.main(Main.java:183) ~[server-1.18.2-20220404.173914-srg.jar%23346!/:?] {re:classloading,re:mixin,pl:mixin:A}
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?] {}
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?] {}
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?] {}
at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?] {}
at net.minecraftforge.fml.loading.targets.CommonServerLaunchHandler.lambda$launchService$0(CommonServerLaunchHandler.java:32) ~[fmlloader-1.18.2-40.1.80.jar%2317!/:?] {}
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:53) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:71) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.modlauncher.Launcher.run(Launcher.java:106) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.modlauncher.Launcher.main(Launcher.java:77) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) [modlauncher-9.1.3.jar%235!/:?] {}
at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:149) [bootstraplauncher-1.0.0.jar:?] {}
Caused by: java.lang.OutOfMemoryError: Java heap space

Error from our side, or is it mopdack related?

Caused by: java.lang.OutOfMemoryError: Java heap space

You need to assign more ram.

It does prevent you doing it with that server provider. There are plenty of other ways and places to run the server depending on your needs and budget.