Hello!
I have the same problem -- especially if it is a very important email. Here are a couple of things that helped me:
1. The email already exists: often I am worried that someone will say something mean or unkind in an email, which is pretty much never the actual case, but I build it up in my mind. Reminding myself that the email already exists and the words already exists helps me get the courage the look at them.
2. Getting in the habit of just opening all the messages, and reminding yourself that these emails are usually either neutral or positive. Most people don't send nasty emails, because setting a tone in an email is very hard to do. Usually if people have bad things to say, they will say it over zoom, etc.! Also that it doesn't leave a great impression is e-mails are not answered long term!
3. Set a deadline: Not all emails have to be answered right away; for very important emails I give myself a hard deadline of 24 hours. However, as soon as I see a very scary email, I am now really trying to open it immediately; waiting makes the anxiety worse. I tell myself 'you are brave', 'usually emails are good', 'you are a reliable person who always answers emails'and
'don't be a chicken shit' and these phrases help me get the nerve to open the emails. However, if the email is VERY scary I sometimes will wait to my 24 hour deadline. Making it a habit that you are the type of person to open emails really is what fixed me hiding from emails.
4. therapy! got myself a kind therapist
you're definitely not the only one with this problem! good luck!