Can't pay with Electrum - invalid password?
Be sure that you are entering the correct password you've set (be careful with added blank spaces, keyboard localization...). You can try to crack your own password if you remember most of it.

Maybe the transactions that you remember were on imported keys? If so, they are only in that encrypted wallet file. Your seed can only restore the keys derived from it.

Electrum servers are all the same and give the same information (they only differ from hardware).