Keep getting kicked back to login through OWA

This relates to our Microsoft Exchange service hosted by yourselves.

I have spent most of the day today attempting to log in, only to either be kicked straight back to the login screen from the login screen with no error message (despite login being successful), or be logged in and then within 30-40 seconds (halfway through drafting an email) get kicked back out to the login screen again.

This is not the first day on which this has happened, and from previous experience this issue seems to occur for only limited time periods; but this is a business email address and I need to access my emails to work.

I am accessing the OWA at https://ex2.mail.ovh.net, using Chrome Version 65.0.3325.181 (though the issue occurs in Microsoft Edge as well) and have tried clearing cache on all my browsers before reloading the site.

Any thoughts on anything else we can try?