Can Spark chats be read by my company's IT admin?

I was chatting with my friend, but the IT person at the company knew that I was chatting with one of the people at the company. Can the IT admin read my chats with other people?
he uses Linux OS

thanks

Spark does not support end-to-end encryption. Messages that flow though the server (and are possibly archived there) can be accessible to administrators of Openfire and the database in which these archives are stored.

Its common for companies to store internal communications. This is usually covered in the employee handbook or acceptable use policy. Having said that, an IT admin should not be reading email or internal communications unless directed to do so by management(usually involving HR).

ps.
MS Teams can also be monitored and chats retrieved.