Fatal error:
Call to undefined function mb_substr()
After moving to my dedicated server (hypervm CP), I got lots of errors.
How do I solve this problem?
It looks like the mbstring extension, which provides that kind of functions, is not installed or enabled : if it was enabled, you'd have a block "mbstring", in the output of phpinfo().
If you are admin of your server, a first idea might be to check for something like
extension=mbstring
In you php.ini file.