Context:
Due to business reasons, we wanted to shut down websitea.com and redirect traffic from websitea.com https://websiteb.com/pages/abc.
Action taken-1: I setup a HTTP/301 redirect for websitea.com in 101domain to https://websiteb.com/pages/abc.
Problem faced: Now when users go to https://websitea.com they get an error of website certificate revoked, whereas when users go to http://websitea.com they get forwarded correctly to https://websiteb.com/pages/abc
Action taken-2: By reading on the internet and based on my very very limited understanding, I have changed the HTTP/301 redirect setup from https://websiteb.com/pages/abc to http://websiteb.com/pages/abc
Request from readers:
1 - Can someone explain why I started getting error in the first place after "Action taken-1"?
2 - Can someone tell me will "Action taken-2" solve my "Problem faced"?
3 - If my "Action taken-2" will not solve my "Problem faced", can someone tell me what I should do so that my problem is solved?
1 - Can someone explain why I started getting error in the first place after "Action taken-1"?
It is unknown why the certificate was revoked for this server, i.e. it might have been initiated by you since you wanted to move away from the site or there might be other reasons. When in doubt contact the CA which issued the certificate to you and ask for the reason.
2 - Can someone tell me will "Action taken-2" solve my "Problem faced"?
No. The problem is that the HTTPS access to websitea.com fails because the certificate for this site was revoked. But working HTTPS access to the HTTPS site you want to redirect FROM is necessary in order for the redirect to proceed, because the redirect gets only known to the browser after successful access to the original site.
3 - If my "Action taken-2" will not solve my "Problem faced", can someone tell me what I should do so that my problem is solved?
You need to get a new (i.e. valid) certificate for websitea.com, i.e. for the site you want to redirect from.