Have you tried using the hardcoded Thunderbird (or similar) oauth credentials to authenticate to Google et al? You can also use davmail to proxy your requests to Office 365 / Exchange and it handles oauth also.

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eamonnsullivan an hour ago | parent [-]

I tried both. The error from davmail suggests it was specifically blocked/prohibit and I failed using actual Thunderbird.

	▲	pfortuny 41 minutes ago \| parent [-]
		Hi, I guess you have already tried. My Uni also made it difficult but I succeeded in setting up a working davmail, using the exchange protocol. Mail my username at gmail.com if you think I can help. Gateway: Exchange Protocol: O365Interactive OWA or EWS (Exchange) URL: https://outlook.office365.com/EWS/Exchange.asmx (follow the instructions at https://davmail.sourceforge.net/faq.html)