I am composing a letter to the owner of my company. In the letter I am trying to describe a situation where a problem occurred due to a confluence of failures. E.g., our tom-foolery server crashed, because the backup failed and the widget was faulty and the wickets were rusty and the elbows weren't bent enough. The system wouldn't have crashed, but for this coincidence of these specific failures.
The phrase that first came to mind was "Perfect Storm" which is defined by MacMillan Dictionary as follows:
a very unpleasant situation in which several bad things happen at once
My example sentence
Normally the server can handle a backup failure without crashing, but that was not the case today due to a ________________.
I am worried that Perfect Storm may not be easily understood in this context. I am hoping that I can find a word or phrase that will be understandable and professional.
I searched all of the major dictionary sites for synonyms to Perfect Storm but I couldn't find any at all. Next, I searched Stack Exchange for similar questions. There are a couple of questions here on ELU that are related to the phrase Perfect Storm, but unfortunately none provide a synonym.
I am hopeful that you can help me. Please feel free to reword my example sentence in any way you would like that will provide a professional understandable synonym for "Perfect Storm" in the context outlined above.