Hello there We have read your message . We try to help you. okay your proton software was not accepted by an installation in Thunderbird . what messages did you receive or error message s. Is your software up to date to the system. tell me more about the installation you are trying? And what computer are you using there? The operating system?Os or Windows? Can you tell me. it is possible to combine it with apple mail and Thunderbird mail software. can you write me where you get stuck trying to configure this for use with Thunderbird? I have parts here to help you out. Greetings firefoxvolunteer.