Hey liz-brown,
Our engineers are aware of this issue in the product and the error appears to be intermittent depending on the behavior of the Paypal website rather than an error with the script.
Most accounts do update after multiple attempts so please try clearing the cache on the browser or logging in through and incognito window and select 'Update' in the banking page - you may have to click this several times before the transactions pull through. Alternately you can upload the transactions manually using a CSV file following our guide here.
Thanks!