Hi Rui,
Thanks for your question. It's really hard to know exactly what is happening without talking to your colleague, but here are some general tips.
1. Empty the cache in your web browser, incluing all temporary internet files and cookies.
2. Look in your web browser settings and make sure that you allow cookies to be stored. The session cookie for Projectplace will expire immediately otherwise and you will have to log in over and over again.
I hope this helps your colleague:)
Best regards,
Karolina