I have had difficulty making a purchase from #DeutscheBahn over the past week or so. The BahnCard is only sold online, and at the payment step I always landed on an error page, with code 751. (On int.bahn.de the error page says it's a 404, but the URL includes errorCode=751.)

I tried on several days, in Firefox and Chromium, on both bahn.de and int.bahn.de, clearing cookies, etc.

I phoned DB on Saturday, but didn't reach anyone who could help with this. Today I phoned again and was transferred to their technical support department, apparently to exactly the right person there. They were able to tell me code 751 indicates bot detection. And since I was not using a VPN and had already tried different browsers, the most likely reason for this was: using Linux.

Sure enough, on Firefox on Windows this worked first time. Maybe a User Agent switcher would also work, but I didn't have one installed.

Yet another example of a European institution favouring dependence on US technology.