On your phone go to Settings, under Apps go to OfferUp
You will see an option to clear cache / data
Uninstall the app.
Restart the phone.
Install the app again.
Start the app and log back into the account.
Do it in that order and you will have finished doing all you can from your end.
If this process doesn't fix it, contact support.
I do remember others having a similar issue, unsure if they gave an update.
https://offerup.com/support/new/
