If it is impossible to restore the communication within two working days, one party must notify the other that  alternative means of communication specified in Article II.5.1 will be used until the supplier portal or the  machine-to-machine connection is restored. When a change in the interface control document requires adaptations, the contractor (or leader in case of a  joint tender) has up to six months from receipt of the notification to implement this change. This period can  be shortened by mutual agreement of the parties. This period does not apply to urgent measures required by  the security policy of the contracting authority to ensure integrity, confidentiality and non-repudiation of  information and the availability of e-PRIOR, which must be applied immediately. The parties agree that any e-document, including related attachments exchanged via e-PRIOR:  The parties expressly waive any rights to contest the validity of such a document solely on the grounds that  communications between the parties occurred through e-PRIOR or that the document has been signed  through e-PRIOR. If a direct connection is established between the parties’ back offices to allow electronic  transfer of documents, the parties agree that an e-document, sent as mentioned in the interface control  document, qualifies as an EDI message.  If the e-document is dispatched through the supplier portal, it is deemed to have been legally issued or sent  when the contractor (or leader in case of a joint tender) is able to successfully submit the e-document without  any error messages. The generated PDF and XML document for the e-document are considered as a proof  of receipt by the contracting authority.  In the event that an e-document is dispatched using a direct connection established between the parties’  back offices, the e-document is deemed to have been legally issued or sent when its status is ‘received’ as  defined in the interface control document.  When using the supplier portal, the contractor (or leader in case of a joint tender) can download the PDF or  XML message for each e-document for one year after submission. After this period, copies of the e- documents are no longer available for automatic download from the supplier portal.  The contractor submits a request for each person who needs to be assigned the role of ‘user’ in e-PRIOR.  These persons are identified by means of EU Login (formerly known as the European Communication  Authentication Service (ECAS)) and authorised to access and perform actions in e-PRIOR within the  permissions of the user roles that the contracting authority has assigned to them.  User roles enabling these e-PRIOR authorised persons to sign legally binding documents such as specific  offers or specific contracts are granted only upon submission of supporting documents proving that the  authorised person is empowered to act as a legal representative of the contractor. II.5.5. Authorised persons in e-PRIOR  II.5.4. Validity and date of e-documents  II.6. LIABILITY  II.6.1  The contracting authority is not liable for any damage or loss caused by the contractor, including any  damage or loss to third parties during or as a consequence of implementation of the FWC.  II.6.2 If required by the relevant applicable legislation of if requested by the contracting authority, the  contractor must take out an insurance policy against risks and damage or loss relating to the  19  (a) is considered as equivalent to a paper document; (b) is deemed to be the original of the document;  (c) is legally binding on the parties once an e-PRIOR authorised person has performed the ‘sign’ action  in e-PRIOR and has full legal effect;  (d) constitutes evidence of the information contained in it and is admissible as evidence in judicial  proceedings. 