If you open the repository this wiki belonged to on Bitbucket website, do you see the option 'Wiki' on the sidebar?
I would like to understand if the option 'Wiki' is missing and you cannot access the wiki at all, or if the issue is different (e.g. the wiki exists, but certain pages you added are not visible). Could you please clarify which is the case?
In case the 'Wiki' option is missing from the sidebar, and you have admin access to this repo, please go to Repository settings > Wiki. If the option No wiki is selected there, then another admin of the repo may have disabled the wiki. Select Private wiki (if that wiki was private), save the changes and let me know if you can view the wiki then.
Thank you for your reply. If I understand correctly, what is missing is a certain page of an existing wiki?
I went ahead and created a support ticket for you for this issue, so one of our engineers can investigate further. I created the ticket using the email of your community account - you should have received an email in your inbox with a link to the ticket. Just in case you haven't received the email, please feel free to let me know, I can post the link here. The ticket is visible only to you and Atlassian staff, no one else can view its contents even if they have the link.
I would like to ask if you could please leave a reply to the support ticket with a) the URL of the wiki with this issue and b) the URL that shows you the message "File doesn't exist", so we can further investigate.
If you have any questions, please feel free to let me know.