******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hello Nektar++, 1. I am trying to run a 3D simulation on a simple geometry using IncNavierStokesSolver with all orthogonal cells and two sets of periodic boundary conditions, but I keep getting this message: Fatal : Level 0 assertion violation unable to determine face orientation I tried using the peralign module with and without the orient parameter with no success. I also went into gmsh and made sure all of the mesh surface normal vectors were pointing inwards but encountered the same error. I have attached my session and geometry files to the bottom of this email as OneDrive links. 2. Is there an issue with the subscription to the Nektar users mailing list? I requested to join Nektar-users around the beginning of May but still have not received the confirmation email. Regards, Isaac [https://res-h3.public.cdn.office.net/assets/mail/file-icon/png/code_16x16.png]geometry.xml<https://uofc-my.sharepoint.com/:u:/g/personal/isaac_rosin1_ucalgary_ca/Eb-tSLIdldFNlNIyrRAekKABj9YrwQLRD0-zpu_VtMG4lg> [https://res-h3.public.cdn.office.net/assets/mail/file-icon/png/code_16x16.png]session.xml<https://uofc-my.sharepoint.com/:u:/g/personal/isaac_rosin1_ucalgary_ca/EX2VvjWkF7RBnXfZJUcqSJABpYl54Ue_wh-1_Ub6Z4XzBg> [https://res.cdn.office.net/assets/mail/file-icon/png/generic_16x16.png]geometry.geo<https://uofc-my.sharepoint.com/:u:/g/personal/isaac_rosin1_ucalgary_ca/Edo3Gy12BFNDhgm2iZ-83wcBecDK_olZahL_SpKiavx4RA>