Script with Skype4py is failing on python2.7

Question

I am running my script on python2.7 and receivng this kind of issue:

X Error of failed request:  BadWindow (invalid Window parameter)
Major opcode of failed request:  25 (X_SendEvent)
Resource id in failed request:  0x300000f
Serial number of failed request:  14
Current serial number in output stream:  14

I tried to google it, but with no success. The point is that it worked fine 2 days ago (on Friday), but now I can't figure it out. I am using skype 4.3.0.37, working on Elementary OS 0.3.2 Freya (64 bit) based on Ubuntu 14.04.

client = Skype(Transport='x11')
client.Attach() 
user = 'myskype'
message = report_list
client.SendMessage(user, message) 

Thanks in advance