SQL Login Method

Hello,
I have in production sql 2014 with instance skype.
And I installed sql 2019 with New instance for skype. When I start sql server management studio i cant connect 2014 side as skypelst.abc.local/skype
skypelst.abc.local/skype but i cant connect 2019 side like this. So skype cant connect New server.
Which settung are missing ?

Regards
Yakup

From your description it is not quite clear what instance names you are using, or whether the instances are on the same windows server. To see the instances that you have installed, Winows+R, type services.msc in the Open: text box, click OK. Look for entries with SQL Server(xxxx) in the name. The value xxxx is the instance name. The value in brackets that reads MSSQLSERVER denotes the default instance. Also, make sure the instances are running.