Hello @Tania28105272a99o,
Thanks for reaching out. Would you mind trying to reset Illustrator's preferences manually as suggested by Myra, and check if that helps resolve the issue:
• Close all Adobe applications.
• Go to the following locations
• ~/Library/Caches
• ~/Library/Application Support/Adobe
• ~/Library/Preferences
• Rename Adobe Illustrator, com.adobe.illustrator and Adobe Illustrator 27 Settings folders to Adobe Illustrator.old, com.adobe.illustrator.old and Adobe Illustrator 27 Settings.old
• Launch Illustrator from the Creative Cloud.
Note: Location starting with this "~" sign indicates the User Library, which is hidden. So, you need to copy & paste the exact path in spotlight search or from Finder Menu > Go > Go to Folder > Paste the location in the dialog box like this:

Disclaimer: Please note that renaming preferences folders will remove all the custom settings, and Illustrator will launch with default settings. You can also save a backup of the folders in case you want to. The location is mentioned above.
If the issue persists, kindly share some more information, like the exact version of the OS/Illustrator installed on your computer, system configuration, and screenshots of the location of these files so we can investigate this further.
Looking forward to your response.
Thanks,
Anubhav