Users were not able to create knowledge article even after adding them to "Can contribute" user criteria.
Write ACL on the kb_knowledge table was blocking the users from accessing and creating knowledge articles.
Please follow the below steps for troubleshooting and finding the cause of the issue:
-Go to ACL's and find if any write ACL is added for kb_knowledge table.
-If you find the ACL then deactivate that ACL and then test the user criteria and it should work.
To understand the User criteria in debt, please find the docs below: