Why is one of my sub-users receiving a form limit message error?

Hello, I have a user account that when they go to create a new form, it is stating that they have reached their limit. I am not sure why this is happening because they are apart of our plan which we have plenty of forms available and they are not on the "Starter" plan

Perhaps you are referring to your sub-users? If yes, please note that sub-users can only edit the form and view submissions of the form shared to them. Your account and their account are different so they need to upgrade as well if they want to create more forms.

What you can do is create a folder and share it with them. Once the folder is shared with your sub-users, they can move the form from their account to the shared folder. It is like they are transferring the form from their account to your account.

To know more about the sub-user feature, please check the guide below:

How-to-Share-Forms-with-a-Sub-Account-User

I have sub-users already in my account. The user from the screenshot is a sub-users within my account. They are trying to create new forms within their shared folder.

Apologies for any confusion. If a sub user has previously had a jotform account, they are able to create forms under their own 'free' accounts. It looks like your sub user already has created 5 forms towards their 'starter' limit. Please advise the user to click 'My Forms' link and transfer their forms into shared folder of your account. They can drag and drop forms. 

Then, when new forms are created in sub user account, those forms can also be dragged into shared folder. This would allow forms to use limits of your main paid account. 

We will be glad to assist if you need more help, just let us know.