Hi debb5, thanks for posting on the Community today
We're aware that some users are currently unable to switch between companies using the gear icon in QuickBooks Online.
This issue has been raised to our investigation team who're working to restore the feature. We've added you to our investigation with reference INV-111442 so that you'll be notified once fixed.
In the meantime, please use the workaround of logging out of QBO completely and logging back in, before selecting the company you want from the account manager (click the blue initial > Manage your Intuit Account > Products & billing > Select the company from list > Go to QuickBooks).
Thanks for your patience while we work to rectify the issue. We'll be here if you need any further support.