CRA autofill limit?

Has anyone used the import from CRA function for a large number of  slips. I have a Managed Investment account that has several trades per month, so I have more than 100 T5008 slips to import in addition to other slips. i was able to import slips for my spouse's return since he has a  small number of forms to input, but mine starts to import, but times out during the Save step. So I was wondering if there is a restriction on how many slips it can import. I have tried doing this with different browser, as well as trying from my Windows 10 laptop and  from my  iphone, but I get the same error each time:

 

Oops, we encountered an error
What happened to my data?
Don't worry! With the exception of the last page you were on, all the data you have
entered so far has been safely saved on our secure server.
What do I do now?
Try going back to the start of the interview and navigating past the step where you
encountered the error.
You can also go to the Return Manager and select a new return to work on.