Upon registration when user chooses birth date you receive error message
ctokepa Hi
I checked that registration page: /регистрация but did not see that field, could you enable so I can replicate this issue?
Enabled it again. Try again.
ctokepa I think something wrong with the Joomla package on your site as when I assign this page: /регистрация to Cassiopeia - a standard template of Joomla but the same issue happens there:
Does this happen after you update Joomla version?
Don't know I have updated it and started working on the website. Should I reinstall and start from scratch?
ctokepa If you've not customized your site much, you can consider to build it again.