I’ve updated to WordPress 5.1 and also updated EE to latest version but as of today, no-one has been able to purchase tickets & get the message in the topic title plus being asked to refresh the page. The only people who seem able to book tickets are WordPress admins. Can you please advise how this can be fixed? The last successful booking was yesterday apart from us as admin. We added 1 plugin last night but have removed it again in case it was causing the problem.