I was saddened to learn that the Danish help forum (I do not remember its official name) – where two extraordinarily helpful and very capable gentlemen for a total of eighteen times (beginning in 2014) promptly offered solutions to problems (that kept me from working). I sincerely wish to thank them! But: being unable to find the aforementioned forum anywhere, I guess I will have to try to state my current problem in English instead (even though this involves the added difficulty of my, being an amateur, not knowing the correct translations of the Danish words used in menus &c. My current problem is this, however: My Firefox Browser (64 bit, version 108.0.1) will no longer allow me to access two (Danish) websites which I have been visiting either daily or several times a week for years (without any difficulty). One of these sites is the (government-run) official Danish Film Institute at https://www.dfi.dk/. I have no difficulty getting access to the first (main) page. But when I click on one of the numerous “subordinate” links there (such as: https://www.dfi.dk/cinemateket/biograf), I (frequently, though not every single time) get “error message,” including this “error code”: SEC_ERROR_REUSED_ISSUER_AND_SERIAL When I search in Mozilla help forums for advice about what to do about this, I am instructed to get in touch with the owner of the site (i.e., The Danish Film Institute). So I called them, and got in touch with their webmaster (I think it was) who informed that, to his knowledge, there was nothing wrong with their “security protocol” (or whatever he called it) and that he had never had a similar complaint from other users. Another site, to which I have (since a number of weeks) systematically been denied access (if I use Firefox – but not if I try Microsoft Edge instead) is a small, not-for-profit, amateur-driven, web-based Danish radio-station (to which I have been listening (and paying my dues) for decades): https://www.radiojazz.dk/. When I try, I get the same error-code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL I did sent an e-mail to the station, but they haven’t answered. (I cannot blame them, they are only a small handful of volunteers.) My operating system is Windows 10 (yes, I know there is a new edition, but at least the one I have is fully updated). Can anyone tell me how to get Firefox to re-install the certificates the browser thinks it is missing? Kind regards, and season’s greetings from Nikolaj Lunoe Copenhagen, Denmark