I have trained Bert on my own data which has been converted to IDs by using BertForMaskedLM, but when I use the model for the further fine-tuned, I found this error 
@LysandreJik
## code info
<!-- You can run the command `transformers-cli env` and copy-and-paste its output below.
     Don't forget to fill out the missing fields in that output! -->
here's my model:


![image](https://user-images.githubusercontent.com/56223656/110211963-61276580-7e99-11eb-8508-42591b5138e6.png)

![image](https://user-images.githubusercontent.com/56223656/110212033-b2cff000-7e99-11eb-8378-116dafe78f8e.png)




## Information

Model I am using my own pre-tained Bert model which is stored in the path "../bert":

The problem arises when using:

![image](https://user-images.githubusercontent.com/56223656/110212083-fb87a900-7e99-11eb-9457-f4b94da1234b.png)
   
here are the files in the path "../bert":

![image](https://user-images.githubusercontent.com/56223656/110212157-55886e80-7e9a-11eb-8b7f-dce93af1b72e.png)

The tasks I am working on is: text matching:
* [ ] my own dataset is like: 

![屏幕快照 2021-03-06 16 29 16](https://user-images.githubusercontent.com/56223656/110211923-2a514f80-7e99-11eb-86ae-c403a7e7001e.png)






## Expected behavior

<!-- A clear and concise description of what you would expect to happen. -->
what exactly is the problem?