Microsoft recently announced the availability of Lync-Skype connectivity . If you haven't been able to get up and running yet, then you've come to the right place. Before you begin though, check out our three most popular answers : 1. The Skype user must be signed in with a Microsoft account (formerly Windows Live ID). 2. If the Skype user is using their own email address as a Microsoft ID (for example, bob@contoso.com instead of bob@outlook.com or something similar) then you have to format their name like this when you add them as a contact: bob(contoso.com)@msn.com. Learn more . 3. To receive contact requests from Skype, the Skype for Business user has to set their alert level as follows: go to Options Alerts Contacts not using Skype for Business and choose Allow invites but block all other communications or Allow anyone to contact me. Did any of these suggestions get you connected? If not, read on (and if you’re an admin, take a look at the Provisioning Guide for Skype for Business-Skype Connectivity )… Lync Server and Skype for Business A Skype for Business user does not receive a contact request from a Skype user This can happen when the Skype for Business user has Skype for Business options set so they are not notified when someone else adds them as a contact. Solution The Skype for Business user must go to Options Alerts General alerts , and then select Tell me when someone adds me to their contact list . A Skype for Business user removes a Skype user, but the Skype user can still see Skype for Business user's presence and send IMs This happens when the Skype for Business user chooses Remove from Group instead of Remove from Contact List. Solution In the Skype for Business main window, click Relationships, and then remove the Skype user from the list. When a Skype for Business user calls a Skype user, the call sometimes fails This currently happens in less than one percent of the cases, and is scheduled to be fixed in the next service update. Workaround Try the call again. NOTE : A fix for this will be available by June 30 as part of the Skype for Business cumulative update. Skype for Business users can't communicate with Skype users who have a Microsoft account with a custom (EASI) domain A Skype for Business user adds a Skype user with a custom Microsoft account such as bob@contoso.com, and can’t see their presence or send them IMs. Workaround Add the contact using the following format: bob(contoso.com)@msn.com, where bob@contoso.com is the custom Microsoft account name of the person you’re trying to contact. For details, see Skype for Business users can't communicate with external contacts who have Microsoft accounts that have a custom (EASI) domain. Office 365 Small Business customers have External communications turned on, but can’t connect to Skype users Before May 20, 2013, turning on External communications for Small Business customers didn’t automatically turn on Skype for Business-Skype connectivity. Now it does. Workaround Switch External communications off and then back on again. Go to Admin Service settings Instant messaging, meetings and conferencing External communications . Skype users Skype users signed in with a new Microsoft account notice a delay of several minutes in seeing the presence status of a newly-added Skype for Business contact This situation occurs when the Skype user signs in with a newly created Microsoft account, and the Skype for Business user has the following alert setting: Options Alerts Contacts not using Skype for Business Allow anyone to contact me . Workaround You can either wait for five minutes, or sign out of Skype and then sign back in. You can then see the Skype for Business user’s presence. A Skype and a Skype for Business user remove each other as contacts, and then attempt to add each other as a contact again, but are not successful This happens when a Skype and a Skype for Business user both remove each other as contacts. When one person tries to add the other contact again, the other person does not receive a contact request. Workaround The Skype for Business and the Skype user must both add each other as contacts again.