All users but one have this behavior. They are all on the same version of iOS and MM app.
I asked the user where it works, but he told me he didn’t do anything different (he’s the boss so I don’t believe him ^^)
They can’t do anything on the Import Key screen except cancel. I guess they have to type in something but I don’t know what.
The way it’s working is:
Our provider has a NGINX RP, on which our HTTPS certificat is installed.
The certificate is CA-signed, valid until 2020 for all our sites.
Our provider had to add specific rules on their RP for notifications to be received by apps or www versions of MM. It worked fine for months.
Behind our provider’s RP, the communication is plain HTTP to our server where MM server is installed with Docker (thus 3 containers: www, app and db).
The server was on version 5.9 and it stopped working with the last iOS update. Then I upgraded the server to 5.16 hoping it’d solve the problem but issue is still here.
It works fine on all Android apps and Web versions.