We had the same problem on a CentOS7 machine. Disabling the VERIFYHOST
VERIFYPEER
did not solve the problem, we did not have the cURL error anymore but the response still was invalid. Doing a wget
to the same link as the cURL was doing also resulted in a certificate error.
-> Our solution also was to reboot the VPS, this solved it and we were able to complete the request again.
For us this seemed to be a memory corruption problem. Rebooting the VPS reloaded the libary in the memory again and now it works. So if the above solution from @clover
does not work try to reboot your machine.