I can’t add/install any new addons from the website. The install button keep asking to download FF. I have the newest FF 61.0.1 installed. Can someone help?
Yikes, that’s no good! This might be caused by a setting or add-on that modifies the user agent.
Could you try installing an extension from addons.mozilla.org in a new profile?
I tried to install addons from new profile but it didn’t work. 
You might want to ask about this on support.mozilla.org.
Hello, since about a month i have the same problem. The cause is, that i add some values to the useragent string and want to keep that. The recognition worked anyway in the past, can this be reworked again?