Invalid Formula

[KevinDax]

Hello,
I have a formula in Airtable which should output "SMS" if certain conditions are met.

This formula has worked for a long time and has not been changed. Now I have noticed that something has been changed in the formula function and Airtable indicates that the formula is incorrect. I can save, but I can't find the error that Airtable is referring to. What am I doing wrong in the formula?

IF(
    AND(
        OR(
            {Terminart} = "Hauptuntersuchung (HU)", 
            {Terminart} = "Sicherheitsprüfung (SP)"
        ), 
        OR(
            AND(
                MONTH(TODAY()) = MONTH({Datum nächste Prüfung fällig}), 
                YEAR(TODAY()) = YEAR({Datum nächste Prüfung fällig})
            ), 
            {Datum nächste Prüfung fällig} < TODAY()
        ), 
        WEEKDAY(TODAY()) = 1
    ), 
    "SMS"
)

Please correct the following errors in the formula:

Missing opening parenthesis "(". at line 3 column 9
Missing opening parenthesis "(". at line 6 column 4
Missing opening parenthesis "(". at line 7 column 5
Missing opening parenthesis "(". at line 8 column 9
Missing opening parenthesis "(". at line 9 column 14
Missing opening parenthesis "(". at line 9 column 20
Missing opening parenthesis "(". at line 9 column 31
Missing opening parenthesis "(". at line 9 column 62
Missing opening parenthesis "(". at line 10 column 12
Missing opening parenthesis "(". at line 10 column 18
Missing opening parenthesis "(". at line 10 column 19
Missing opening parenthesis "(". at line 10 column 59
Missing opening parenthesis "(". at line 11 column 3
Missing opening parenthesis "(". at line 12 column 40
Missing opening parenthesis "(". at line 12 column 41
Missing opening parenthesis "(". at line 14 column 3
Missing opening parenthesis "(". at line 14 column 9
Missing opening parenthesis "(". at line 14 column 10
Missing opening parenthesis "(". at line 14 column 11

[kuovonne · Accepted solution]

The Airtable formula editor tends to show wavy red underlines even when the formula is correct, especially with multi-line formulas. If the formula saves and gives the correct result, you can ignore the wavy red underlines.