Would you mind sharing more details on what you're having trouble e with? Please let us know what project you are working on (post or video? What kind of export are you trying to get (JPG, PNG, or PDF)? Are you unable to save any project? When saving a project, are you referring to Adobe Express Web's auto-saving feature, or are you talking about the exporting project?
I'd suggest you try once after clearing the cache/cookies of the browser and checking the system requirements. If the issue persists, please share the details with us to investigate this; sharing a screen recording of the workflow helps us the best.