+ Start a Discussion

unable to create formula field

I am trying to finish the creation of a formula field in the trail head module,but was facing with this error.

<--Challenge Not yet complete... here's what's wrong: 
There was an unexpected error in your org which is preventing this assessment check from completing: System.DmlException: Insert failed. First exception on row 0; first error: REQUIRED_FIELD_MISSING, Required fields are missing: [types__c, model__c]: [types__c, model__c]--> 

here comes the screen shot of the work i did.
User-added image

I created formula field on the case object-fields-custom fields,the field accessibility is given to all the profiles out there.
can anyone help me out where i have made the mistake..

i can reckon i have gone somehere silly.. 
help appreciated..

Saurabh BSaurabh B
Try adding brackets... it should work ... ...

 (Today()- Account.LastActivityDate)

Please mark this as Best Answer if it helps you...
Please check if you have created any validation rules on Opportunity as part of the previous trail head module. My guess is there should be a validation rule which is preventing the record to Save.
i  tried adding brackets and even looked at the validation rules there are no validation rules on either opportunity or case.. 
I tried this same  formula task for another org of mine, it worked there.There is no error as such as the below one. I want anyone to explain what are all the possibilities for this particular error . [Stated- i have deactivated all the validation rules(i didn't find any but only one )]. I have googled for this error but not able to understand .

User-added image
Sorry dude, its going to be a trial and error only. Are there any triggers which fires based on the updates on Cases.
I even saw that whether the type(type__c in error snapshot)and model(model__c in error snapshot) are present in the page layout of the case object also) they are present.