Hi,
As per the screenshot, it seems that you are trying to save data on Account entity email field.
And in email field, you are trying to add the multiple email Ids separated by semicolon.
But the email fields in dynamic contains the validation to validate the email address and Email field should have only one email id.
Hence you are getting the error.
Now, if you want to store the multiple email Ids then you can use Email, EmailAddress2 and EmailAddress3 fields of account entity as shown below.

Also, if i understand the above need correctly then you have some system/tool integrated with dynamic crm to send mass email and you want only one fields with multiple email Ids separated by semicolon.
So, i would suggest you to have some Textarea type of fields and there you can store multiple email Ids separated by semicolon.
Here, only additional step we need to take is to add some custom validation to validate the group of email ids.
Thanks,
Pradeep.
Please mark this as VERIFIED if it helps.