Project linking fails

Hi !
I've just entered a new account in Zoho CRM. I also linked a contact to this account. Then I tried to link the account to a Zoho Project as I did for other account. But, it failed. I received no error message.

I should also say that the account name was Zen & Cie before and as I thought the & could be a problem, I changed it to Zen et Cie. I tried again to link it to his Zoho Project but it still didn't work.

Any idea ?