Outlook connection to exchange server lost

Hello,

my outlook 2013 cannot establish a connection to Exchange server (Office 365) since 8. july, here is what I tried:

1. reinstall MS Office

2. shut down firewall / antivirus

3. import registry keys from a user, who has connection

4. create new account - POP3-SMTP account was running, new exchange account not

5. create an account on colleague's PC - this account was working, also, I am able to connect through browser to e-mail and one drive, not able to connect to one drive through explorer view

Thank you for any help!

Martin