@thenamaskar Yes I did , I am starting to suspect there is problem with my account or hosting , I recently posted a problem stating about the problem with mysql in my account
I just tried to upload the private key from your Let’s Encrypt cert to the client area. That worked without any issues.
As the installation instructions say, please make sure to upload the ENTIRE content of the box in the client area. That includes the lines with the dashes, those are actually part of the key text.
I checked it thanks to @Admin private key was all set but I swear when I tried to upload the certificate it showed me error I mentioned in the question. And BTW I am using my phone for copying the certificate ( starting from ----Begin certificate---- to -----end certificate----- )can that cause the problem
The problem is solved I think there was some kind of hidden ASCII character when I copied the certificate and key using my mobile now I am using my PC and everything went smoothly