Not enough memory (even though 2gb is free)
OMG seriously? The solution is right there in front of you, if you bother to read it.
In response to JimDeadlock ():
OMG seriously? The solution is right there in front of you, if you bother to read it.
Has perms.
You are the second person with that problem recently. Maybe it's actually something wrong with build I dunno.
Yea, after adding the second plugin NO plugins load, with or without players and right after restart. Nothing I do makes the plugins load. Super frustrating.
In response to 2CHEVSKII ():
You are the second person with that problem recently. Maybe it's actually something wrong with build...
Unlikely since nothing has changed and only 2 out of hundreds of thousands aren’t having the issue.

The amount of memory available to the game server may not be what the server itself has available.
In response to Wulf ():
Unlikely since nothing has changed and only 2 out of hundreds of thousands aren’t having the issue.<...
Will not argue, it's really strange situation. 
To OP -> devil's always in details, you might have been missing something (Access rights/Mem allocated to specific process maybe?)
In response to JimDeadlock ():
OMG seriously? The solution is right there in front of you, if you bother to read it.
The [Warning] is just an assumption from Oxide. The actual error is "Out of memory".
In response to Wulf ():
The [Warning] is just an assumption from Oxide. The actual error is "Out of memory".
The error has to be a false positive. My rust server has access to all the RAM on that server (8GB) and when the error is occuring its using 4,3 - 4,5 GB RAM. For refrence I am using the pterodactyl.io hosting panel, and I have allocated the server with 8000 MB ram. Also the server is running Ubuntu 18.
In response to tommyvange ():
The error has to be a false positive. My rust server has access to all the RAM on that server (8GB)...
Well, linux have never been the best solution for rust hosting...
In response to 2CHEVSKII ():
Well, linux have never been the best solution for rust hosting...
Thats right, but it should still work with plgins. I have hosten on linux (pterodactyl.io) before and it worked just fine.

Merged post

@Wulf I did some testing, and I can confirm that my server has more than enough available RAM to reload plugins. Here is a screenshot right after I ran "o.reload BetterChat" https://i.gyazo.com/a6b4f66c97b289347c576357449e7b18.png. As you can see in the screenshot the server is only using 4.8 out of 7.6 GB RAM.
I have to disagree with the anti-Linux comments :) I use LinuxGSM on local machines, I've had rustserver + Oxide on Ubuntu 18.04, Debian Stable and Arch, never had any problems at all, I add/remove plugins all the time while the server is online and the whole thing is super stable and easy to manage.

To me it seems like an issue with your host. There was someone else on these forums the other day complaining about some weirdness with their pterodactyl.io host - they use some kind of weird virtual container setup, it wouldn't surprise me if RAM supply/detection in one part of the system was different to another. I wonder if OrangeDoggo is on pterodactyl.io as well?
In response to JimDeadlock ():
I have to disagree with the anti-Linux comments :) I use LinuxGSM on local machines, I've had rustse...
Pterodactyl is just a web panel for managing the servers easier but it might have something to do with my using Hetzner cloud instead of a dedi? Or it might be a docker bug?
In response to JimDeadlock ():
I have to disagree with the anti-Linux comments :) I use LinuxGSM on local machines, I've had rustse...
I'm not using any web panels,I'm just starting it up from the terminal & Ctrl+A+D out of the screen.
I reinstalled my server using CentOS instead of Ubuntu, and its working like a charm now :)
In response to tommyvange ():
I reinstalled my server using CentOS instead of Ubuntu, and its working like a charm now :)
I've had this issue on Ubuntu,Centos