Working at Le Mans pre 24hour race about 5 years ago, hundreds of us Brits from motor racing had all sorts of cards blocked. 3 failed attempts with a card and it's blocked. CHAOS

I ended up with only my Barclaycard working and paying out over 15K for race team purchases as so many of the teams cards had been blocked.
The explanation was that the French data transmissions had a 'speed issue/overload' as there were so many attempted transactions and the computers couldn't process the foreign transaction data quick enough so the transaction is refused by the banks computers.
More recently a Deutsche Bank expert on card use told us that card refusal in hotels, shops or at automated machines such as pumps on the continent is often due to slow data transmission. ie the receiving system isn't getting data re your foriegn card fast enough so refuses the transaction.
Try placing the card in machines, pause, and then enter pin slowly sometimes works in counter terminals and pumps
I always brim the tank on Saturday if travelling in France and I have E LeClerc and others on the Satnav if I'm not using the Autoroute as there equipment normally more up to date

Italian friends showed us how they never pay at most French automated Autoroute pay stations
