Why might LinkedIn swear?

Question

Social media

Hello everyone, today I decided to deal with my LinkedIn profile, I am adding new entries to the "courses" section, after I added the 50th entry, while saving the 51st entry, it gives an error:
"The information entered in some form fields is invalid. Check the information you provided." .
And only one possible "OK" button. What should I do to add the 21st entry?

Answer 1

it is clear that the limits