Hello @sodipyme,
Thanks for contacting us. I hope you are doing well.
Please make sure, you have set default values for all your required fields, you can check this from Support > Custom Fields > Ticket fields.
Also, make sure, you have checked the checkboxes for GDPR and terms and conditions at the end of the ticket form as shown in the attachment.
https://www.awesomescreenshot.com/image/42194570?key=907e9137af74bc986f0fe2a55c7fa7f4
If this does not resolve the issue, please try on different browser and using different users.
Thank you.