IAS 21069 Personal Tax/VAT Filer- After HMRC ‘Grant Authority’ your PC browser loads up a white screen and 9999
Article ID
personal-tax-vat-filer-after-hmrc-grant-authority-your-pc-browser-loads-up-a-white-screen-and-error
Article Name
IAS 21069 Personal Tax/VAT Filer- After HMRC ‘Grant Authority’ your PC browser loads up a white screen and 9999
Created Date
4th August 2025
Problem
Resolution
Personal Tax/VAT Filer- When you get the HMRC sign in screen and log in using your ASA and click the ‘Grant Authority’ option, your PC browser will then load up either with a login OR a warning and the PT/VAT will then show a error and it will stop VAT/PT HMRC data retrieval from working. This may show differently for pcs.
The address field at the very top of the browser shows this text: Localhost:9999/login?code=XXXXXXX
The text Localhost:9999 is from IRIS but if there is something installed on the affected machine that uses the port 9999 then that accidently intercepts the IRIS process and stops it working causing the pc browser to pop up and an error to show in PT/VAT.
ACRONIS: If you have ‘Acronis‘ installed on the affected pc then please disable it first, then log into the HMRC with ASA and you will not get the browser white screen anymore. There is a reported issue with Acronis were it is blocking the IRIS process at port 9999, so review the use of this on affected pcs and disable when submitting VAT and PT, once it has been submitted, enable it again and try and submit on another client. NOTE: Acronis may have been working fine before but a recent update from Acronis could now cause this issue.
If you do not have Acronis installed on the pc then review all installed security/antivirus software’s and run a test by switching one of them off and then login to HMRC with ASA login etc. If that fails switch the next one off and test again, so run this until all are switched off and if the HMRC login with ASA now works then its very likely one of the security/antivirus software installed causing this issue.
Case 1) Browser loads with Sign in screen and get error like ‘Login web browser window encountered a error’
Case 2) Browser loads with Text appears and get error like ‘Unable to cast object of type. System.windows.threading.dispather Iris.Tax.Communications.HMRCAPI.webbrowserview
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