Hi @CarlaR
It could be a security issue, but it could be other things also.
Does anyone else have your password?
Do you have Zoom installed on any other actual computers - rather than other devices? Zoom will only log you out like this if there is another sign-in from from another device of the same type.
A sign-in means, in this case, just means the Zoom client being connected to Zoom - not necessarily connected to a Meeting. If that helps for context?
If you have a standalone password with Zoom (if your account is not connected to organization, like with SSO) and if this event is still inexplicable, I would recommend changing your Zoom password at https://zoom.us/profile and then also click "Sign Me Out From All Devices" at that same page.
Depending on your level of access in Zoom, or the critically or sensitivity of your account, you may also like to enable MFA as an added security measure.
https://support.zoom.us/hc/en-us/articles/360038247071-Setting-up-and-using-two-factor-authentication-2FA-