TCPDF error on booking - anyone else seeing this in last few days

I have had two people see this error but i can not see it ?

TCPDF error !! not sure what it means but when it happens payment fails and booking form locks the days up so the user can NOT rebook?

and ideas for a quick fix ?

is there a way to free up slots if a payment fails ? automatically ?

Hi Scottadam,
Please submit ticket and send your site url with super admin account. I will check the problem with TCPDF for you. By the way, when the payment is failure, the order status will be changed to Cancelled and the timeslots will be free
Thanks
Dam