Hi,
Any changes to PHP recently or any modifications to the php.ini?
Just pasting this error message in Google I found
What it boiled down to for me was that due to a forgotten comment in configs I was using mod_php with mpm_event apache. So non-thread-safe php7 in a threaded environment, hence shared memory corruption and a number of problems, one of them being sha1 was unavailable after some random uptime.
reboot resolved this issue