Hi Clare123, does this happen specifically when saving and closing an invoice? If it's happening at other times, we can extend your inactivity timeout to three hours to avoid immediate logout.
To do this, go to Settings > Account and Settings > Advanced > Other Preferences > Edit the Sign me out if inactive for to 3 hours.
However, if this issue only occurs when saving an invoice, I recommend logging in to your account in incognito mode to check if it is a temporary browser problem.
If the issue resolves after this process, please ensure your browser is up to date. You can also use other supported browsers.
Please let us know if you require further assistance.
