That was weird. When I was working on the transfer to another host, I noticed that I could no longer install the anti-spam plugin that I have used for years and which I was happy about (WP Spamshield). It proves to have been taken out of the plugin store because it is no longer maintained. Too bad!
I had one day without anti spam plugin and already caught a couple, so I have installed a plugin that I have no experience with (conveniently called “Anti-Spam”), so I hope it does not make any problems for ‘real people’. Let me know if this is the case.