You maybe had this issue in the transports since the new online ticket validation system has been implemented on April 1st.
Now you must scan a QR code to validate the tickets, and many issues were reported:
The time to validate is too short, the applications are not working well, and you must wait a long time to validate the ticket, avoiding the possibility to enter the transports in time.
One of the issues, only after 1 attempt:
Before this new system was implemented, it was easier to validate online tickets, Since this update, people are often obliged to buy physical tickets. A restrictive and potentially contaminating solution.
Moreover, the QR codes are often difficult to find in the transports, which can make you lose time and risk being controlled and fined. Something absolutely unacceptable considering the situation.
Feel free to sign this petition to try to change things and find a convenient solution.