Data with the same Exchange keys exist

Question

i am using visual studio,unity and photon to build my online game,
while yesterday, when my internet down, my server cannot be login anymore.

in unity, i get the error message:
ArgumentException: Can't use encryption yet. Exchange keys first.

in visual studio, i get the error message
類型 'System.ArgumentException' 的未處理例外狀況發生於 Photon3Unity3D.dll 其他資訊: Can't use encryption yet. Exchange keys first. In english, it should be :
System.ArgumentException on Photon3Unity3D.dll other information:Can't use encryption yet. Exchange keys first. (sorry for some Chinese, i hope i translate it correctly)

I believe the problem i got is that when my internet down, some keys are stored in my computer and do not deleted successfully, is this the case?
If yes, may i know how can i reset the keys in my computer?
If not, can anyone tell me how can i solve this problem?
Thank you!

Answer 1

Finally found the problem.
After the internet down, the computer IP address have been changed.
And by resetting the IP, the problem is solved